syncing email between devices

How is the account set up?

POP3 does not support synchronizing multiple clients.

IMAP and Exchange accounts will synchronize all changes between the server and all clients using the same protocol.

Mine is setup as IMAP on all my devices and it doesn’t work anymore so is there another way or do i have to start all of with setting up my email?

Please check with your Mail provider or use iCloud.

Turn on iCloud on both devices, that is the most simple method.