Yep that is the latest version! Does your Nextcloud login name contain any ‘special’ characters e.g. umlaut, spaces or whatsoever? What you can try to do is enable the logging in the registry (make sure Outlook is disabled) this would be ‘DebugMode=true’. Then start Outlook, try to connect through the settings dialog a few times. The log can be found in your my documents folder as yyyyMMdd_nextcloud_outlook.log. Can you PM me the log then?
For the 64 bits version… strange, are you sure 64 bits Office is installed?
Because it sounds that the 64 bits registration is failing, whilst the 32 bits works.