Emails not being recieved

I've been using my account with Zoho for a while now. Lately, though, while I can easily send emails and the recipient does receive them, I cannot get any incoming emails, either replies or new emails being sent. THe only thing that has shown up in my email in several weeks is a message saying that the the domain of an email I tried to send did not resolve but that it will keep trying

I've triple checked this, the sender did reply to my email, but Zoho isn't letting anything through except error messages.