This is a Google Play Services issue, seems related to the device's connectivity, happens most often on mobile data.
Please remove the Aqua Mail "authorization grant" here:
https://myaccount.google.com/permissionsSwitch the phone to a WiFi connection.
Add the account as Gmail type, should work, save it.
Check mail there once.
Long press on the account -> account setup -> enable the checkbox labeled "Force web based login" (below the email) and press Next
You should get new window with Google's web site inside, where you will need to log in again re-typing your password, and then grant the permission again for Aqua Mail to access your mail
Complete and save
Now Aqua Mail will use its own OAUTH2 code and not Google Play Services
If any of the above should fail:
- Please allow access to "less secure apps" here:
https://www.google.com/settings/security/lesssecureapps- Add the account into Aqua Mail as "Internet Mail" account type
PS - "less secure" means "send the password to log in, over an
encrypted (of course) network connection