Browser authentication issue?
If you have issues authenticating, please ensure Chrome browser is installed and it is the default browser. If issue persist try clearing data for Chrome browser in Android App settings. Firefox has also been reported by some users to work. Simple browsers on app store that use an internal standard WebView with not be able to work with the security measures Google is enforcing.
If using PCloud on EU server the redirect when authenticating in browser needs to work - manually entering code will not work.