diff --git a/apps/run.go b/apps/run.go
index 9b168544..ec1e34a0 100644
--- a/apps/run.go
+++ b/apps/run.go
@@ -2,6 +2,7 @@ package apps
 
 import (
 	"archive/tar"
+	"bufio"
 	"bytes"
 	"compress/gzip"
 	"context"
@@ -12,7 +13,6 @@ import (
 	"mime/multipart"
 	"net"
 	"net/http"
-	"net/http/httputil"
 	"net/url"
 	"os"
 	"os/signal"
@@ -322,42 +322,43 @@ func (runCtx *runContext) connectToRunServer(ctx context.Context) (*http.Respons
 		return nil, nil, errgo.New("No attach URL to connect to")
 	}
 
-	req, err := http.NewRequest("CONNECT", runCtx.attachURL, nil)
+	url, err := url.Parse(runCtx.attachURL)
 	if err != nil {
 		return nil, nil, errgo.Mask(err, errgo.Any)
 	}
-	token, err := runCtx.scalingoClient.GetAccessToken(ctx)
 
+	// Establish an initial TCP connection
+	conn, err := net.Dial("tcp", url.Host)
 	if err != nil {
-		return nil, nil, errgo.Notef(err, "fail to generate auth")
+		return nil, nil, errgo.Mask(err, errgo.Any)
 	}
-	req.SetBasicAuth("", token)
 
-	url, err := url.Parse(runCtx.attachURL)
+	// Wrap with TLS if using HTTPS
+	if url.Scheme == "https" {
+		tlsConfig := config.TLSConfig.Clone()
+		tlsConfig.ServerName = strings.Split(url.Host, ":")[0]
+		conn = tls.Client(conn, tlsConfig)
+	}
+
+	req, err := http.NewRequest("CONNECT", runCtx.attachURL, nil)
 	if err != nil {
 		return nil, nil, errgo.Mask(err, errgo.Any)
 	}
 
-	dial, err := net.Dial("tcp", url.Host)
+	token, err := runCtx.scalingoClient.GetAccessToken(ctx)
 	if err != nil {
-		return nil, nil, errgo.Mask(err, errgo.Any)
+		return nil, nil, errgo.Notef(err, "fail to generate auth")
 	}
+	req.SetBasicAuth("", token)
 
-	var conn *httputil.ClientConn
-	if url.Scheme == "https" {
-		host := strings.Split(url.Host, ":")[0]
-		tlsConfig := config.TLSConfig.Clone()
-		tlsConfig.ServerName = host
-		tlsConn := tls.Client(dial, tlsConfig)
-		conn = httputil.NewClientConn(tlsConn, nil)
-	} else if url.Scheme == "http" {
-		conn = httputil.NewClientConn(dial, nil)
-	} else {
-		return nil, nil, errgo.Newf("invalid scheme format %s", url.Scheme)
+	// Write the HTTP request directly to the connection
+	err = req.Write(conn)
+	if err != nil {
+		return nil, nil, errgo.Mask(err, errgo.Any)
 	}
 
-	res, err := conn.Do(req)
-	if err != httputil.ErrPersistEOF && err != nil {
+	resp, err := http.ReadResponse(bufio.NewReader(conn), req)
+	if err != nil {
 		if err, ok := err.(*net.OpError); ok {
 			if err.Err.Error() == "record overflow" {
 				return nil, nil, errgo.Newf(
@@ -371,8 +372,11 @@ func (runCtx *runContext) connectToRunServer(ctx context.Context) (*http.Respons
 		return nil, nil, errgo.Mask(err, errgo.Any)
 	}
 
-	connection, _ := conn.Hijack()
-	return res, connection, nil
+	if resp.StatusCode != http.StatusOK {
+		return resp, nil, nil
+	}
+
+	return resp, conn, nil
 }
 
 func (runCtx *runContext) validateFiles(files []string) error {
diff --git a/apps/run_test.go b/apps/run_test.go
index 4a00f905..0319d42f 100644
--- a/apps/run_test.go
+++ b/apps/run_test.go
@@ -1,6 +1,8 @@
 package apps
 
-import "testing"
+import (
+	"testing"
+)
 
 func TestParseEnvVar(t *testing.T) {
 	ctx := &runContext{}
diff --git a/go.mod b/go.mod
index 8c1ccef4..c5f40e93 100644
--- a/go.mod
+++ b/go.mod
@@ -14,6 +14,7 @@ require (
 	github.com/dustin/go-humanize v1.0.1
 	github.com/fatih/color v1.18.0
 	github.com/go-git/go-git/v5 v5.12.0
+	github.com/golang/mock v1.6.0
 	github.com/google/go-github/v47 v47.1.0
 	github.com/gorilla/websocket v1.5.3
 	github.com/gosuri/uilive v0.0.4
@@ -27,7 +28,7 @@ require (
 	github.com/urfave/cli/v2 v2.27.5
 	golang.org/x/crypto v0.29.0
 	golang.org/x/term v0.26.0
-	golang.org/x/text v0.20.0
+	golang.org/x/text v0.21.0
 	gopkg.in/errgo.v1 v1.0.1
 )
 
@@ -45,7 +46,6 @@ require (
 	github.com/go-git/go-billy/v5 v5.6.0 // indirect
 	github.com/golang-jwt/jwt/v4 v4.5.1 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
-	github.com/golang/mock v1.6.0 // indirect
 	github.com/google/go-querystring v1.1.0 // indirect
 	github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99 // indirect
 	github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51 // indirect
diff --git a/go.sum b/go.sum
index e086b262..3784d45d 100644
--- a/go.sum
+++ b/go.sum
@@ -201,8 +201,8 @@ golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
 golang.org/x/text v0.4.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
-golang.org/x/text v0.20.0 h1:gK/Kv2otX8gz+wn7Rmb3vT96ZwuoxnQlY+HlJVj7Qug=
-golang.org/x/text v0.20.0/go.mod h1:D4IsuqiFMhST5bX19pQ9ikHC2GsaKyk/oF+pn3ducp4=
+golang.org/x/text v0.21.0 h1:zyQAAkrwaneQ066sspRyJaG9VNi/YJ1NfzcGB3hZ/qo=
+golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.1.1/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 97f4b059..0cbdbffd 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -300,7 +300,7 @@ golang.org/x/sys/windows
 # golang.org/x/term v0.26.0
 ## explicit; go 1.18
 golang.org/x/term
-# golang.org/x/text v0.20.0
+# golang.org/x/text v0.21.0
 ## explicit; go 1.18
 golang.org/x/text/cases
 golang.org/x/text/internal