Can't send email, Part 2

I have a new problem.  When I try to send an email (P0P-3), the screen goes 
white.  I can still see the email, but it is blurred.  I cannot save the 
email, but must disregard.

This problem exists whether I am using [email protected] (my local internet 
service provider) or [email protected] which goes through siteground.

And, if I reboot, kmail will send the first email just find but screen goes 
white when I try to send later emails.

My secretary's email is working fine (she uses same kmail as do I).

For example, I had to reboot in order to send this email.

Debian Buster
kmail 5.9.3

Any suggestions?

John