Emails not being delivered to Outlook

Emails not being delivered to Outlook

Emails are not being delivered to my Outlook inbox today.  Has been working fine up until today and I have not made any changes to configuration.  Emails sent from Outlook are being received by recipient, but do not appear in "Sent Items".  Incoming emails are there when I log on to Zoho online account, just not in Outlook.  Is there an IMAP problem?  When will it be fixed?