diff --git a/scripts/diagnose-shop-service.sh b/scripts/diagnose-shop-service.sh
index c0ed2ad..4b69c62 100644
--- a/scripts/diagnose-shop-service.sh
+++ b/scripts/diagnose-shop-service.sh
@@ -28,16 +28,20 @@ else
 fi
 echo
 
-echo "4. www-data доступ"
+echo "4. Порт 3000"
+ss -tlnp | grep ':3000' || echo "  порт 3000 свободен"
+echo
+
+echo "5. www-data доступ"
 sudo -u www-data test -r "$SHOP_ROOT/package.json" && echo "  package.json: OK" || echo "  package.json: FAIL"
 sudo -u www-data test -x "$SHOP_ROOT" && echo "  каталог: OK" || echo "  каталог: FAIL"
 echo
 
-echo "5. Тест Node (5 сек)"
+echo "6. Тест Node (5 сек)"
 set +e
 timeout 8 sudo -u www-data bash -c "cd '$SHOP_ROOT' && set -a && source .env 2>/dev/null && set +a && node src/server.js" 2>&1 | head -20
 set -e
 echo
 
-echo "6. journalctl shop"
+echo "7. journalctl shop"
 journalctl -u shop -n 30 --no-pager 2>/dev/null || true
diff --git a/scripts/free-port-3000.sh b/scripts/free-port-3000.sh
new file mode 100644
index 0000000..719b56f
--- /dev/null
+++ b/scripts/free-port-3000.sh
@@ -0,0 +1,31 @@
+#!/bin/bash
+# Освободить порт 3000 (ручной npm start / старый процесс)
+set -euo pipefail
+
+PORT="${1:-3000}"
+
+if ! command -v ss >/dev/null; then
+  echo "ss не найден"
+  exit 0
+fi
+
+if ! ss -tlnp | grep -q ":${PORT} "; then
+  echo "Порт ${PORT} свободен"
+  exit 0
+fi
+
+echo "Порт ${PORT} занят:"
+ss -tlnp | grep ":${PORT} " || true
+
+if command -v fuser >/dev/null; then
+  echo "Останавливаем процессы на ${PORT}/tcp..."
+  fuser -k "${PORT}/tcp" 2>/dev/null || true
+  sleep 2
+fi
+
+if ss -tlnp | grep -q ":${PORT} "; then
+  echo "Порт ${PORT} всё ещё занят — остановите процесс вручную"
+  exit 1
+fi
+
+echo "Порт ${PORT} свободен"
diff --git a/scripts/install-shop-service.sh b/scripts/install-shop-service.sh
index ae4e3d0..0d949f5 100644
--- a/scripts/install-shop-service.sh
+++ b/scripts/install-shop-service.sh
@@ -78,6 +78,9 @@ fi
 systemctl daemon-reload
 systemctl enable shop
 
+systemctl stop shop 2>/dev/null || true
+bash "$SCRIPT_DIR/free-port-3000.sh" 3000
+
 echo "Запуск shop..."
 if ! systemctl restart shop; then
   echo ""
@@ -89,13 +92,20 @@ if ! systemctl restart shop; then
 fi
 
 sleep 3
-if curl -sf http://127.0.0.1:3000/health; then
-  echo ""
-  echo "OK — служба shop запущена"
-  systemctl status shop --no-pager | head -15
-  systemctl reload caddy 2>/dev/null || true
-else
-  echo "shop не отвечает на :3000"
+
+if ! systemctl is-active --quiet shop; then
+  echo "shop.service не в состоянии active"
+  journalctl -u shop -n 40 --no-pager
+  exit 1
+fi
+
+if curl -sf http://127.0.0.1:3000/health; then
+  echo ""
+  echo "OK — служба shop запущена (systemd active)"
+  systemctl status shop --no-pager | head -15
+  systemctl reload caddy 2>/dev/null || true
+else
+  echo "health не отвечает"
   journalctl -u shop -n 40 --no-pager
   exit 1
 fi
diff --git a/scripts/server-update.sh b/scripts/server-update.sh
index 3183515..1853c2d 100644
--- a/scripts/server-update.sh
+++ b/scripts/server-update.sh
@@ -35,6 +35,7 @@ fi
 
 if [ -f /etc/systemd/system/shop.service ]; then
   systemctl daemon-reload
+  bash "$SCRIPT_DIR/free-port-3000.sh" 3000 2>/dev/null || true
   systemctl restart shop
   sleep 2
   if curl -sf http://127.0.0.1:3000/health; then
diff --git a/src/server.js b/src/server.js
index a27bdeb..35d5ab4 100644
--- a/src/server.js
+++ b/src/server.js
@@ -96,7 +96,13 @@ async function start() {
   });
 
   server.on('error', (err) => {
-    console.error('Не удалось запустить сервер:', err.message);
+    if (err.code === 'EADDRINUSE') {
+      console.error(
+        `Порт ${PORT} уже занят (часто старый «npm start»). Выполните: bash scripts/free-port-3000.sh`
+      );
+    } else {
+      console.error('Не удалось запустить сервер:', err.message);
+    }
     process.exit(1);
   });
 }
@@ -107,8 +113,12 @@ start().catch((err) => {
     console.error('  systemctl start postgresql');
     console.error('  bash scripts/setup-postgres-ubuntu.sh');
     console.error('  Проверьте DATABASE_URL в .env');
+  } else if (err.code === 'MODULE_NOT_FOUND') {
+    console.error('Не найден модуль:', err.message);
+    console.error('  cd', path.join(__dirname, '..'), '&& npm install --omit=dev');
   } else {
     console.error('Ошибка запуска:', err.message);
+    if (err.stack) console.error(err.stack);
   }
   process.exit(1);
 });
diff --git a/wiki/Troubleshooting.md b/wiki/Troubleshooting.md
index 55afa8e..62a6633 100644
--- a/wiki/Troubleshooting.md
+++ b/wiki/Troubleshooting.md
@@ -52,6 +52,26 @@ cp /opt/shop/shop10.bak.*/.env /opt/shop/shop10/.env 2>/dev/null || cp /opt/shop
 bash /opt/shop/shop10/scripts/server-update.sh
 ```
 
+## shop.service: exit-code / activating (auto-restart)
+
+**Health ответил OK, но systemd падает** — часто порт 3000 занят старым `npm start`:
+
+```bash
+cd /opt/shop/shop10
+git pull
+sudo bash scripts/free-port-3000.sh
+sudo systemctl restart shop
+systemctl status shop
+```
+
+Лог:
+
+```bash
+journalctl -u shop -n 30 --no-pager
+# EADDRINUSE → free-port-3000.sh
+# MODULE_NOT_FOUND → npm install --omit=dev
+```
+
 ## Job for shop.service failed (control process exited)
 
 Чаще всего не запущен PostgreSQL или не прошёл `ExecStartPre`: