Merge pull request #6255 from nextcloud/enh/noid/improve-ghcr.io-check

mastercontainer: improve check for ghcr.io

Author: szaimen

Containers/mastercontainer/start.sh

@@ -274,10 +274,11 @@ fi
 
 # Check if ghcr.io is reachable
 # Solves issues like https://github.com/nextcloud/all-in-one/discussions/5268
-if ! curl https://ghcr.io &>/dev/null; then
+if ! curl --no-progress-meter https://ghcr.io/v2/ >/dev/null; then
     print_red "Could not reach https://ghcr.io."
     echo "Most likely is something blocking access to it."
-    echo "You should be able to fix this by using https://github.com/nextcloud/all-in-one/tree/main/manual-install"
+    echo "You should be able to fix this by following https://dockerlabs.collabnix.com/intermediate/networking/Configuring_DNS.html"
+    echo "Another solution is using https://github.com/nextcloud/all-in-one/tree/main/manual-install"
     exit 1
 fi