When checking my email the 'Thunderbird' status bar says "downloading message' (as normal), but sometimes the message does not appear in my Inbox or any folder. I'm using Thunderbird 115.12.0 on Linux Ubuntu. The email is downloaded via the POP protocol. I have checked on the server and nothing is left there. Using the Thunderbird search function on 'date' only, the e-mails actually in the inbox or folders show up, not the one purported to have been downloaded. All of my folders are set to 'Unthreaded'. Any ideas please?