E-Mail disappeared after moving to another folder

Hello. I’m using K-9 for a couple of years with one e-mail account. No problems. Since one year I use three accounts. One is my old POP3 account. The other two are IMAP accounts. Today something happened that I cannot understand.

Somebody sent me an e-mail to an IMAP account. I couldn’t find the mail. After a while I found it in a folder called ‘calendar’. I think, it’s because there was an .ics attachment. I marked the e-mail and moved it to the inbox folder. The e-mail disappeared. I cannot find it anymore.

I use Thunderbird on my PC. I tried to find the e-mail there. Unsuccessful. I logged in online via internet browser to Groupwise and searched for the e-mail. Unsuccessful. The e-mail has gone but I don’t know where.

I tried to understand this and sent another e-mail with an .ics attachment to the IMAP account. The mail was automatically sorted in the ‘calendar’ folder. I could open it, read it and so on. Then I closed it, marked it and moved it to the inbox folder. The same happened. The mail vanished.

This is reproducible. Does anybody know, what happens here?

K9 doesn’t filter/sort/move mail automatically, so it is most likely your mail account - at the server level - that is moving around messages with .ics attachments. I don’t use Groupwise, but this does look like something it might be doing. I would start by looking at the filter and rule operators set up on your Groupwise account. Some of these may be set by the system administrator.