I've previously used the Windows PopTray utility to monitor my emails in my old mail provider (BT, in the UK), using the POP3 protocol. That worked fine, showing waiting messages, and allowing me to preview or delete any of them.
I've now switched over to using Zoho as a mail provider, still using POP3 (I know, I know, I ought to be using IMAP!), and having reconfigured all my various mail clients on Windows, iOS and Android and they're working fine, sending and receiving mail. However, although PopTray still lists messages correctly, and can delete them, it can no longer preview them (i.e. it can't fetch the message bodies).
Using the original Poptray 3.2, the preview window is now just blank (no headers or body text), and updating to the latest PopTrayU 5.2.6 is similar, except that it also fails with an error "Unable to retrieve message. Connection closed gracefully" when trying to preview the contents of a message.
I've obviously enabled POP access in Zoho (since that's what all my clients are using for retrieval), and I'm sure the PopTray settings are correct (poppro.zoho.com, POP3 with SSL/TLS on port 995, and the correct credentials, and with the SSL plugin installed), not least because it correctly lists waiting messages with all the header details such as subject and sender, and also can also correctly delete messages from the server.
I realise this is an issue with PopTray, not a problem with Zoho Mail (which is great!), but hoped that someone might have experienced this themselves or have some suggestions as to what might be causing it. I've looked in the PopTray forums but can't see any obvious clues. Unfortunately I can't see any way to log the POP dialog between PopTray and Zoho, which might make it obvious what's going wrong. It's not a disastrous problem, but it's a nuisance no longer being able to quickly preview message in PopTray and identify any spam that gets through Zoho's own filtering.