old emails are being rereceived when using outlook

old emails are being rereceived when using outlook

i am using outlook 2016 desktop and my email is set to use pop access.
since a week ago i have been receiving emails that have been received in the past as new unread emails.
i realy do not know what had happened but today i have received almost 76 mb 550 emails from months ago as if i had not received them at all.
i have not changed my settings or anything, not on zoho and not on my outlook account settings.
what could have caused this issue?
do you have any idea or solution?
best regards