this is my first entry in the forum so thank you in advance for your help and your patience…
I installed Em Client last week and it’s really great except for one tiny issue : when I try to answer some e-mails (it seems kinf of random to me), I get this message :
Do these emails have something in common, like having an attachment for example? I’m not a power user but some users in this forum are far more knowledgeable and might help you. Meanwhile, could you try the following?
Could you connect to your mail server using a web interface? Are these emails present in your inbox and can you reply to them?
If you look in Menu > Operations, do you see any IMAP errors in the Log tab (if you use IMAP of course).
Have you considered disabling your antivirus/firewall application, then restarting eM Client? Maybe your AV/firewall are blocking some emails for some reason.