Php error during install windows client

Nextcloud version 14 running on a hosted server. windows 10 (64 bit). Client 2.5.1 Client installs but Receive the following error when connecting to my nextcloud instance.:

The Requested URL /index.php/login/flow was not found on this server
Additionally, a 404 not found error was encountered while trying to an ErrorDocument to handle this request.

Clueless on how to solve this problem. Which server? MY ISP’s server or Nextcloud?

How do I fix both issues?