This occasionally happens with my phone.
If a soft reboot by turning the phone Off and On does not resolve this I go into Settings and accounts and delete the account and re enter the email account and password which usually resolves this.
I use the Samsung Email app.
I wish you all the best.
Daily Driver > Samsung Galaxy s²² Ultra 256Gb in Phantom Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "