In my country it is now common to turn on “whitelisting” on mobile operators so that only certain state-funded services are accessible, including mail providers. Problem is that when sending chatmail relay is inaccessable, you need to manually go into Settings>Advanced Settings>Relays>Enter Password and only then you can change relay to state mail provider to be able to send messages. Tedious doing it once but when you get home and want better sending speeds - go do everything again. Little annoyance for me and a dealbreaker for everyone else in my family.
Expected behavior
When sending relay is not accessable, automatically choose from available to become new sending relay (or from preselected)
Actual behavior
Need to go through tedious process of manually selecting relay when messages are stuck sending