diff --git a/Dockerfile b/Dockerfile
index f47986f..535dce5 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -16,7 +16,11 @@ COPY package.json package-lock.json .npmrc ./
 RUN if [ -n "$NPM_TOKEN" ]; then \
       echo "//mirror.soroushasadi.com/repository/npm-group/:_authToken=${NPM_TOKEN}" >> .npmrc ; \
     fi \
-  && npm ci
+  && npm ci \
+  && echo "=== post-install check ===" \
+  && (test -d node_modules/next \
+      && echo "OK: node_modules/next found: $(cat node_modules/next/package.json | grep '\"version\"' | head -1)" \
+      || (echo "FATAL: node_modules/next is missing after npm ci" && exit 1))
 
 ENV NEXT_TELEMETRY_DISABLED=1
 COPY . .