diff --git a/internal/runner/options.go b/internal/runner/options.go
index 9bdd93a..c7cd014 100644
--- a/internal/runner/options.go
+++ b/internal/runner/options.go
@@ -1,6 +1,7 @@
 package runner
 
 import (
+	"errors"
 	"math"
 	"os"
 	"path/filepath"
@@ -142,6 +143,10 @@ func ParseOptions() (*Options, error) {
 		readFlagsConfig(flagSet, options.ConfigDir)
 	}
 
+	if len(options.UpstreamHTTPProxies) > 0 && len(options.UpstreamSOCKS5Proxies) > 0 {
+		return nil, errors.New("can't use upstream HTTP proxies and upstream SOCKS5 proxies at the same time")
+	}
+
 	if cfgFile != "" {
 		if !fileutil.FileExists(cfgFile) {
 			gologger.Fatal().Msgf("given config file '%s' does not exist", cfgFile)
diff --git a/internal/runner/runner.go b/internal/runner/runner.go
index 6f27352..8f37b03 100644
--- a/internal/runner/runner.go
+++ b/internal/runner/runner.go
@@ -112,7 +112,8 @@ func (r *Runner) Run() error {
 
 	if len(r.options.UpstreamHTTPProxies) > 0 {
 		gologger.Info().Msgf("Using upstream HTTP proxies: %s\n", r.options.UpstreamHTTPProxies)
-	} else if len(r.options.UpstreamSOCKS5Proxies) > 0 {
+	}
+	if len(r.options.UpstreamSOCKS5Proxies) > 0 {
 		gologger.Info().Msgf("Using upstream SOCKS5 proxies: %s\n", r.options.UpstreamSOCKS5Proxies)
 	}
 
diff --git a/proxy.go b/proxy.go
index f46e26a..ff35e89 100644
--- a/proxy.go
+++ b/proxy.go
@@ -523,7 +523,8 @@ func (p *Proxy) getRoundTripper() (http.RoundTripper, error) {
 		roundtrip = &http.Transport{Proxy: func(req *http.Request) (*url.URL, error) {
 			return url.Parse(p.rbHTTP.Next())
 		}, TLSClientConfig: &tls.Config{InsecureSkipVerify: true}}
-	} else if len(p.options.UpstreamSOCKS5Proxies) > 0 {
+	}
+	if len(p.options.UpstreamSOCKS5Proxies) > 0 {
 		// for each socks5 proxy create a dialer
 		socks5Dialers := make(map[string]proxy.Dialer)
 		for _, socks5Proxy := range p.options.UpstreamSOCKS5Proxies {