diff --git a/middleware/distributor.go b/middleware/distributor.go
index d626941456..5ede75b0d9 100644
--- a/middleware/distributor.go
+++ b/middleware/distributor.go
@@ -27,6 +27,46 @@ type ModelRequest struct {
 	Group string `json:"group,omitempty"`
 }
 
+func selectPreferredAffinityChannel(
+	c *gin.Context,
+	preferred *model.Channel,
+	modelName string,
+	usingGroup string,
+	getAutoGroups func(string) []string,
+	isChannelEnabledForGroupModel func(string, string, int) bool,
+) (*model.Channel, string) {
+	if preferred == nil {
+		service.ClearCurrentChannelAffinity(c, "preferred affinity channel missing")
+		return nil, ""
+	}
+	if preferred.Status != common.ChannelStatusEnabled {
+		service.ClearCurrentChannelAffinity(c, fmt.Sprintf("preferred affinity channel %d is disabled", preferred.Id))
+		return nil, ""
+	}
+
+	if usingGroup == "auto" {
+		userGroup := common.GetContextKeyString(c, constant.ContextKeyUserGroup)
+		autoGroups := getAutoGroups(userGroup)
+		for _, g := range autoGroups {
+			if isChannelEnabledForGroupModel(g, modelName, preferred.Id) {
+				common.SetContextKey(c, constant.ContextKeyAutoGroup, g)
+				service.MarkChannelAffinityUsed(c, g, preferred.Id)
+				return preferred, g
+			}
+		}
+		service.ClearCurrentChannelAffinity(c, fmt.Sprintf("preferred affinity channel %d no longer matches auto groups for model %s", preferred.Id, modelName))
+		return nil, ""
+	}
+
+	if isChannelEnabledForGroupModel(usingGroup, modelName, preferred.Id) {
+		service.MarkChannelAffinityUsed(c, usingGroup, preferred.Id)
+		return preferred, usingGroup
+	}
+
+	service.ClearCurrentChannelAffinity(c, fmt.Sprintf("preferred affinity channel %d no longer matches group %s for model %s", preferred.Id, usingGroup, modelName))
+	return nil, ""
+}
+
 func Distribute() func(c *gin.Context) {
 	return func(c *gin.Context) {
 		var channel *model.Channel
@@ -101,29 +141,17 @@ func Distribute() func(c *gin.Context) {
 
 				if preferredChannelID, found := service.GetPreferredChannelByAffinity(c, modelRequest.Model, usingGroup); found {
 					preferred, err := model.CacheGetChannel(preferredChannelID)
-					if err == nil && preferred != nil {
-						if preferred.Status != common.ChannelStatusEnabled {
-							if service.ShouldSkipRetryAfterChannelAffinityFailure(c) {
-								abortWithOpenAiMessage(c, http.StatusForbidden, i18n.T(c, i18n.MsgDistributorChannelDisabled))
-								return
-							}
-						} else if usingGroup == "auto" {
-							userGroup := common.GetContextKeyString(c, constant.ContextKeyUserGroup)
-							autoGroups := service.GetUserAutoGroup(userGroup)
-							for _, g := range autoGroups {
-								if model.IsChannelEnabledForGroupModel(g, modelRequest.Model, preferred.Id) {
-									selectGroup = g
-									common.SetContextKey(c, constant.ContextKeyAutoGroup, g)
-									channel = preferred
-									service.MarkChannelAffinityUsed(c, g, preferred.Id)
-									break
-								}
-							}
-						} else if model.IsChannelEnabledForGroupModel(usingGroup, modelRequest.Model, preferred.Id) {
-							channel = preferred
-							selectGroup = usingGroup
-							service.MarkChannelAffinityUsed(c, usingGroup, preferred.Id)
-						}
+					if err != nil {
+						service.ClearCurrentChannelAffinity(c, fmt.Sprintf("preferred affinity channel %d lookup failed: %v", preferredChannelID, err))
+					} else {
+						channel, selectGroup = selectPreferredAffinityChannel(
+							c,
+							preferred,
+							modelRequest.Model,
+							usingGroup,
+							service.GetUserAutoGroup,
+							model.IsChannelEnabledForGroupModel,
+						)
 					}
 				}
 
diff --git a/middleware/distributor_test.go b/middleware/distributor_test.go
new file mode 100644
index 0000000000..dffd35473f
--- /dev/null
+++ b/middleware/distributor_test.go
@@ -0,0 +1,88 @@
+package middleware
+
+import (
+	"net/http/httptest"
+	"testing"
+
+	"github.com/QuantumNous/new-api/common"
+	"github.com/QuantumNous/new-api/constant"
+	"github.com/QuantumNous/new-api/model"
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/require"
+)
+
+func newDistributorTestContext() *gin.Context {
+	rec := httptest.NewRecorder()
+	ctx, _ := gin.CreateTestContext(rec)
+	ctx.Set("channel_affinity_cache_key", "new-api:channel_affinity:v1:codex cli trace:default:test-affinity-key")
+	ctx.Set("channel_affinity_ttl_seconds", 60)
+	return ctx
+}
+
+func TestSelectPreferredAffinityChannelClearsDisabledChannel(t *testing.T) {
+	ctx := newDistributorTestContext()
+
+	selected, group := selectPreferredAffinityChannel(
+		ctx,
+		&model.Channel{Id: 42, Status: common.ChannelStatusAutoDisabled},
+		"gpt-5",
+		"default",
+		func(string) []string { return []string{"default"} },
+		func(string, string, int) bool { return true },
+	)
+
+	require.Nil(t, selected)
+	require.Empty(t, group)
+
+	anyInfo, ok := ctx.Get("channel_affinity_log_info")
+	require.True(t, ok)
+	info, ok := anyInfo.(map[string]interface{})
+	require.True(t, ok)
+	require.Equal(t, true, info["stale_affinity_cleared"])
+	require.Equal(t, "preferred affinity channel 42 is disabled", info["stale_affinity_reason"])
+}
+
+func TestSelectPreferredAffinityChannelFallsBackForAutoGroupMismatch(t *testing.T) {
+	ctx := newDistributorTestContext()
+	common.SetContextKey(ctx, constant.ContextKeyUserGroup, "default")
+
+	selected, group := selectPreferredAffinityChannel(
+		ctx,
+		&model.Channel{Id: 42, Status: common.ChannelStatusEnabled},
+		"gpt-5",
+		"auto",
+		func(string) []string { return []string{"group-a", "group-b"} },
+		func(string, string, int) bool { return false },
+	)
+
+	require.Nil(t, selected)
+	require.Empty(t, group)
+
+	anyInfo, ok := ctx.Get("channel_affinity_log_info")
+	require.True(t, ok)
+	info, ok := anyInfo.(map[string]interface{})
+	require.True(t, ok)
+	require.Equal(t, true, info["stale_affinity_cleared"])
+	require.Equal(t, "preferred affinity channel 42 no longer matches auto groups for model gpt-5", info["stale_affinity_reason"])
+}
+
+func TestSelectPreferredAffinityChannelUsesMatchingAutoGroup(t *testing.T) {
+	ctx := newDistributorTestContext()
+	common.SetContextKey(ctx, constant.ContextKeyUserGroup, "default")
+
+	selected, group := selectPreferredAffinityChannel(
+		ctx,
+		&model.Channel{Id: 43, Status: common.ChannelStatusEnabled},
+		"gpt-5",
+		"auto",
+		func(string) []string { return []string{"group-a", "group-b"} },
+		func(group, modelName string, channelID int) bool {
+			return group == "group-b" && modelName == "gpt-5" && channelID == 43
+		},
+	)
+
+	require.NotNil(t, selected)
+	require.Equal(t, 43, selected.Id)
+	require.Equal(t, "group-b", group)
+	require.Equal(t, "group-b", common.GetContextKeyString(ctx, constant.ContextKeyAutoGroup))
+}
diff --git a/service/channel_affinity.go b/service/channel_affinity.go
index 9f89585fac..f541a0861a 100644
--- a/service/channel_affinity.go
+++ b/service/channel_affinity.go
@@ -511,6 +511,43 @@ func appendChannelAffinityTemplateAdminInfo(c *gin.Context, meta channelAffinity
 	})
 }
 
+func appendChannelAffinityClearedAdminInfo(c *gin.Context, reason string) {
+	if c == nil {
+		return
+	}
+	reason = strings.TrimSpace(reason)
+	if reason == "" {
+		reason = "stale affinity cleared"
+	}
+
+	if anyInfo, ok := c.Get(ginKeyChannelAffinityLogInfo); ok {
+		if info, ok := anyInfo.(map[string]interface{}); ok {
+			info["stale_affinity_cleared"] = true
+			info["stale_affinity_reason"] = reason
+			c.Set(ginKeyChannelAffinityLogInfo, info)
+			return
+		}
+	}
+
+	info := map[string]interface{}{
+		"stale_affinity_cleared": true,
+		"stale_affinity_reason":  reason,
+	}
+	if meta, ok := getChannelAffinityMeta(c); ok {
+		info["reason"] = meta.RuleName
+		info["rule_name"] = meta.RuleName
+		info["using_group"] = meta.UsingGroup
+		info["model"] = meta.ModelName
+		info["request_path"] = meta.RequestPath
+		info["key_source"] = meta.KeySourceType
+		info["key_key"] = meta.KeySourceKey
+		info["key_path"] = meta.KeySourcePath
+		info["key_hint"] = meta.KeyHint
+		info["key_fp"] = meta.KeyFingerprint
+	}
+	c.Set(ginKeyChannelAffinityLogInfo, info)
+}
+
 // ApplyChannelAffinityOverrideTemplate merges per-rule channel override templates onto the selected channel override config.
 func ApplyChannelAffinityOverrideTemplate(c *gin.Context, paramOverride map[string]interface{}) (map[string]interface{}, bool) {
 	if c == nil {
@@ -623,6 +660,28 @@ func ShouldSkipRetryAfterChannelAffinityFailure(c *gin.Context) bool {
 	return meta.SkipRetry
 }
 
+func ClearCurrentChannelAffinity(c *gin.Context, reason string) bool {
+	if c == nil {
+		return false
+	}
+	cacheKey, _, ok := getChannelAffinityContext(c)
+	if !ok || cacheKey == "" {
+		return false
+	}
+	cache := getChannelAffinityCache()
+	if _, err := cache.DeleteMany([]string{cacheKey}); err != nil {
+		common.SysError(fmt.Sprintf("channel affinity cache delete failed: key=%s, err=%v", cacheKey, err))
+		return false
+	}
+	c.Set(ginKeyChannelAffinitySkipRetry, false)
+	if meta, ok := getChannelAffinityMeta(c); ok {
+		meta.SkipRetry = false
+		c.Set(ginKeyChannelAffinityMeta, meta)
+	}
+	appendChannelAffinityClearedAdminInfo(c, reason)
+	return true
+}
+
 func MarkChannelAffinityUsed(c *gin.Context, selectedGroup string, channelID int) {
 	if c == nil || channelID <= 0 {
 		return
diff --git a/service/channel_affinity_cache_test.go b/service/channel_affinity_cache_test.go
new file mode 100644
index 0000000000..4f295a4458
--- /dev/null
+++ b/service/channel_affinity_cache_test.go
@@ -0,0 +1,54 @@
+package service
+
+import (
+	"testing"
+	"time"
+
+	"github.com/QuantumNous/new-api/common"
+	"github.com/stretchr/testify/require"
+)
+
+func TestClearCurrentChannelAffinity(t *testing.T) {
+	originalRedisEnabled := common.RedisEnabled
+	common.RedisEnabled = false
+	t.Cleanup(func() {
+		common.RedisEnabled = originalRedisEnabled
+		_ = getChannelAffinityCache().Purge()
+	})
+
+	cache := getChannelAffinityCache()
+	_ = cache.Purge()
+
+	cacheKey := "new-api:channel_affinity:v1:codex cli trace:default:test-affinity-key"
+	require.NoError(t, cache.SetWithTTL(cacheKey, 42, time.Minute))
+
+	ctx := buildChannelAffinityTemplateContextForTest(channelAffinityMeta{
+		CacheKey:       cacheKey,
+		TTLSeconds:     60,
+		RuleName:       "codex cli trace",
+		SkipRetry:      true,
+		UsingGroup:     "default",
+		ModelName:      "gpt-5",
+		RequestPath:    "/v1/responses",
+		KeySourceType:  "gjson",
+		KeySourcePath:  "prompt_cache_key",
+		KeyHint:        "test...key",
+		KeyFingerprint: "abcd1234",
+	})
+
+	require.True(t, ClearCurrentChannelAffinity(ctx, "preferred affinity channel 42 is disabled"))
+
+	_, found, err := cache.Get(cacheKey)
+	require.NoError(t, err)
+	require.False(t, found)
+	require.False(t, ShouldSkipRetryAfterChannelAffinityFailure(ctx))
+
+	anyInfo, ok := ctx.Get(ginKeyChannelAffinityLogInfo)
+	require.True(t, ok)
+	info, ok := anyInfo.(map[string]interface{})
+	require.True(t, ok)
+	require.Equal(t, true, info["stale_affinity_cleared"])
+	require.Equal(t, "preferred affinity channel 42 is disabled", info["stale_affinity_reason"])
+	require.Equal(t, "codex cli trace", info["rule_name"])
+	require.Equal(t, "default", info["using_group"])
+}