If the "prevent phone from sleeping while the app is in foreground" is checked, this should mean that, if I'm using the app, the phone shouldn't fall asleep. Except the opposite is true: If this setting is unchecked, the phone won't go to sleep.
@busnbike SMT apps are dead. They were sold to ad company. There is already fork https://github.com/FossifyOrg. Release should in 2-3 weeks. SMTP apps from F-Droid are safe.
If the "prevent phone from sleeping while the app is in foreground" is checked, this should mean that, if I'm using the app, the phone shouldn't fall asleep. Except the opposite is true: If this setting is unchecked, the phone won't go to sleep.