diff --git a/acme.sh b/acme.sh
index 320e22af2f..38ccaadeda 100755
--- a/acme.sh
+++ b/acme.sh
@@ -2519,19 +2519,19 @@ _startserver() {
   _content_len="$(printf "%s" "$content" | wc -c)"
   _debug _content_len "$_content_len"
   _debug "_NC" "$_NC $SOCAT_OPTIONS"
-  _socaterr="$(_mktemp)"
+  export _SOCAT_ERR="$(_mktemp)"
   $_NC $SOCAT_OPTIONS SYSTEM:"sleep 1; \
 echo 'HTTP/1.0 200 OK'; \
 echo 'Content-Length\: $_content_len'; \
 echo ''; \
-printf '%s' '$content';" 2>"$_socaterr" &
+printf '%s' '$content';" 2>"$_SOCAT_ERR" &
   serverproc="$!"
-  if [ -f "$_socaterr" ]; then
-    if grep "Permission denied" "$_socaterr" >/dev/null; then
-      _err "socat: $(cat $_socaterr)"
+  if [ -f "$_SOCAT_ERR" ]; then
+    if grep "Permission denied" "$_SOCAT_ERR" >/dev/null; then
+      _err "socat: $(cat $_SOCAT_ERR)"
       _err "Can not listen for user: $(whoami)"
       _err "Maybe try with root again?"
-      rm -f "$_socaterr"
+      rm -f "$_SOCAT_ERR"
       return 1
     fi
   fi
@@ -2541,10 +2541,12 @@ _stopserver() {
   pid="$1"
   _debug "pid" "$pid"
   if [ -z "$pid" ]; then
+    rm -f "$_SOCAT_ERR"
     return
   fi
 
   kill $pid
+  rm -f "$_SOCAT_ERR"
 
 }