kmail pop3 stuck on fetching email

I have kmail running with an account using pop3. It is stuck (seemingly permanently) on ‘Fetching message 976 of 1137 (10137 of 113637 KB) for …’

How can I identify which email is causing the problem so I can delete it from the mail server using webmail?

When dealing with lots of mail you may consider using fetchmail and postfix instead of kmail, see:

AFAIK, KMail POP3 pulls the e-Mails on an ID basis – “lowest ID first; highest ID last”.You could take a look at the Web-Mail interface, to see if around the 161th e-Mail from the newest in the Post-Box is suspicious …

Alternatively, you could check the last e-Mail pulled by POP3 into KMail and then, go searching for that e-Mail in the Web-Mail interface – the next newest e-Mail is possibly the culprit – don’t delete it – try to download it via the Web-Mail interface and then move it off to a folder in the Postbox «POP doesn’t know about folders in the Postbox».
The downloaded e-Mail can then be imported into a KMail folder.