"Sign in failed". How do I stop it?

[davidffei]

I have an email account which I no longer have access to obtaining new emails (and sending emails). I've disabled the syncing of that email account on my S7 Edge yet this message keeps appearing and I believe it's draining my battery in its attempt to sync. I don't want to completely remove the email account as I need access to the old emails. What am I missing? TIA