Hi @Rene_B 

Thanks for posting in our business forum.

Rene_B wrote

Hello,
I have a question, we have switched to IP telephones in our company, the telephone system is in the cloud. The Yealink T54W work without problems and the mobile DECT phones also only the Yealink T58WPro de register themselves from time to time, are there settings that I have to activate in the network, router is an ER8411.
Thank you very much

Not sure what it has anything to do with the ER8411.

Does this phone need to be set up? What does it need to be set up?

If it only requires the Internet for the phone call, then there is nothing special to be configured.