[horde] only RSET accepted now

[Twilek]

Sorry, this is a copy of the mail I sent previously, somehow the HTML  
mode completely borked the fromating.

> RSET is the SMTP reset command. No idea why your server thinks it    
> should only be sent such a command. Perhaps your message is above  
> the   message_size_limit, or some other part of your stack is  
> failing due to   the size?

I checked the exim config. I have not set a size limit, so it should  
be at 50 MB by default.  But the error triggers way below that. I  
cannot really pinpoint when the error started (maybe it was an exim  
update). I use exim version 4.88 (debian package). The source file  
which generates the error "smtp_in.c" has seen some commits in the  
last months. Maybe some subtle behaviour change of exim has been  
introduced.

Regards
Henning