The app is trying to tell you it's been having trouble accessing your email servers. The origin of these issues is usually outside the app (the network, the servers, maybe different settings).
We know the app didn't change in the last few days, so something else must have.
I would recommend:
1) double-checking the account's settings (esp. vs. the other apps), by long pressing on the account, then account setup, then next to verify
2) rebooting the devices.