I've encountered a strange problem with a particular gmail account when configured in Outlook on iOS.

Account was working fine up until some time on Monday, at which time it stopped sending and receiving. Same problem on both iPhone and iPad. If I configure it in native iOS mail app it works fine.

Even stranger is that if it set the account up on a 3rd iOS device from scratch it downloads all messages up until Monday, but nothing beyond that - and again will not send anything.

Other Gmail accounts are working in Outlook on all of these devices.