Not getting any new mail

Hello,

I have zoho mail account that is configured in Thunderbird 3.1.9 as POP account using pop.zoho.com port 995. Several days ago I stopped receiving any new mail in Thunderbird. The server apparently reports that there is no new mail. Using web browser I can see that there is indeed new mail in my account, but nothing is being fetched by Thunderbird.
I searched forum and found out about mailpop.zoho.com.
I changed my Thunderbird settings to use that and status bar started to show that there are new messages, but connection times out every time at download of the very first message.
As a last resort I reconfigured my Thunderbird to use IMAP, enabled it in zoho settings everything looked fine at the beginning, but when all messages appeared to be fetched, it turned out, that I got only the same set of messages that I had on my POP setup. I didn't get any messages that arrived since that mysterious moment.
Could someone help me get my mail in the mail client? I ran out of ideas at this point.

Thank you,
vladvm.