email not arriving

My account has stopped receiving emails.  I can still send emails, which arrive promptly.  But the last email I received was over 30 hours ago, and I usually receive several dozen emails a day. Emails I send to my Comcast account from other services don't generate any bounce or error message.  They just never appear in my Xfinity.com inbox. Rebooting my cable box had no effect.  Web browsing and streaming are working fine.