Error connecting V1 Bridge

I got an replacement Pixel 9 phone and had to reinstall Hue Essentials.
Working on old Phone without problem.

On new phone no bridge found in search.
Manual entry seems to find the bridge and asks to press the link button.

Then error message: "Die Bridge ist nicht erreichbar. prüfen sie ihre Internetverbindung.

Beforehand I installed Hue V1 App. Bridge was found without issue.

Phone and Bridge in same subnet. Switch/Router is a Fritzbox 7530.

Any Idea in how to proceed?
Thank you.