I'm getting this same issue.
Specifically, when going to my.hostname.tld:2083:
Login page shows up just fine, login shows as successful (if you check Admin side of login, port 2087, the user you tried logging in with shows as logged in), but the login page itself shows 404 not found, with cwpsrv in the footer.
Further reading into the logs shows a lot of errors that reference the following file:
/usr/local/cwpsrv/htdocs/resources/admin/addons/ajax/ajax_dashboard.php
But the way that it shows as being referenced (error on line 0) makes me feel that this is not the root problem.
Also shown is a reference to the cwpsrv socket for PHP, located at:
/usr/local/cwp/php71/var/sockets/cwpsrv.sock
This started after applying the newest update, currently showing update number:
0.9.8.840