After migration to new server, windows client can't connect

after successfully migrating a nextcloud installation to a new server and restarting the nextcloud windows client, this message appears and even after granting access, the client can’t connect. Is there a way to resolve this without any action on the client’s side?

Security warning If you are not trying to set up a new device or app, someone is trying to trick you into granting them access to your data. In this case do not proceed and instead contact your system administrator.

moved it to clients as it may be a client problem?

@perler Have you found any solution to this or do you know any workarround to fix it?
Thanks