cPanel is now more secure and added a Security Token feature to WHM and cPanel. Because of this url's now look like server.tld:2087/cpsessXXXXXXXXX/ where the XXXXXX are numbers.
Quote
Request Info:
Requested page: /cgi/softaculous/index.php
Error message: security token missing
Form Data:
Key
Value
Because of this new feature you need sometimes to relogin when going from Softaculous Auto to cPanel (back to controlpanel button) or click in the WHM menu on Softaculous - Instant Installs.