Mozilla Thunderbird ceased to have new letters on the IMAP protocol. 

The letters are received only when the program is started, then manually receiving mail and automatic does not accept mail. Observed on all clients are Mozilla and MSOutlook.

The checkbox "Allow immediate server notifications when new messages arrive" in Thunderbird" is set in 3 minute, but it does not help. 

I have a domain on Zoho (alvona.сom). We see the problem for a week already. 

The new installation of the Mozilla does not help.

Changing the settings on the imppro.zoho.eu does not help.