diff --git a/t/cli/test_tls_over_tcp.sh b/t/cli/test_tls_over_tcp.sh
index 383b138f00f8d..dd558e6272064 100755
--- a/t/cli/test_tls_over_tcp.sh
+++ b/t/cli/test_tls_over_tcp.sh
@@ -44,8 +44,9 @@ curl -k -i http://127.0.0.1:9080/apisix/admin/stream_routes/1  \
     -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d \
     '{"upstream":{"nodes":{"127.0.0.1:9101":1},"type":"roundrobin"}}'
 
-sleep 0.1
-if ! openssl s_client -connect 127.0.0.1:9100 -servername test.com -CAfile t/certs/mtls_ca.crt | \
+sleep 1
+if ! echo -e 'mmm' | \
+    openssl s_client -connect 127.0.0.1:9100 -servername test.com -CAfile t/certs/mtls_ca.crt | \
     grep 'OK FROM UPSTREAM';
 then
     echo "failed: should proxy tls over tcp"