Hello.
As per your FAQ on app not checking mail.
"If the app is not already whitelisted, there will be a green panel / button / message / prompt asking you to do this."
Pressing this message fixes the problem for a short while, then mail is not received unless the app is opened, and the message is back again.
Phone is an Oppo Reno Z
Is there a save setting in AquaMail to fix this recurring problem, or is this a problem with Oppo phones