OEM mail client help

Error message 5.7.8  authorization failed.  I need a quick fix for this because not receiving any mail since Sunday night at 9:o8 pm

Hi Teresa,

I will be glad to help you.
Can you please specify few more things?
Who is your email service provider?
Is there any chance that you are using two-step verification with that account?
When exactly this error pops out and when this issue started?

Kind Regards