u/cdr-nil

I've been informed by pCloud support that access to a number of API method calls (e.g. collection_list) has been removed. This has been effected by disabling username/password authentication. OAUTH2 authentication can be granted but is also blocked for these method calls.

The methods that still support authentication are related to file operations (e.g. uploadfile), which is why applications like rclone will continue to work.

So, if you are having problems getting your pCloud app to work, this could be the cause.