diff --git a/src/core.sh b/src/core.sh
index be97ea3..31dd05e 100644
--- a/src/core.sh
+++ b/src/core.sh
@@ -172,6 +172,11 @@ update_caddyfile_fallback() {
         # Prepend a new global block at the very top of the Caddyfile
         echo -e "{\n  https_port 4443\n}\n$(cat $is_caddyfile)" >$is_caddyfile
     fi
+    
+    # 4. Replace any explicit :443 in other conf files inside /etc/caddy/sing-box/
+    if [[ -d /etc/caddy/sing-box ]]; then
+        sed -i 's/:443\b/:4443/g' /etc/caddy/sing-box/*.conf 2>/dev/null
+    fi
 }
 
 install_haproxy() {
@@ -197,6 +202,12 @@ restore_caddy_default() {
         sed -i 's/:4443[[:space:]]*{/:443 {/g' $is_caddyfile
         sed -i 's/https_port 4443/https_port 443/g' $is_caddyfile
     fi
+    
+    # Restore explicit :4443 in other conf files inside /etc/caddy/sing-box/
+    if [[ -d /etc/caddy/sing-box ]]; then
+        sed -i 's/:4443\b/:443/g' /etc/caddy/sing-box/*.conf 2>/dev/null
+    fi
+    
     systemctl restart caddy >/dev/null 2>&1
 }