Server denies E-Mail with 300k as too big

Kopano works fine with webapp, but using an iphone I already get an error with a 300 k attachment:
E-Mails können nicht gesendet werden, Die Nachricht wurde vom Server abgelehnt, da sie zu groß ist.

postconf message_size_limit results ind:
message_size_limit = 40960000

Kopano Core installiert
z-push 2.6.2-1 installiert

Univention 4.4-8 errata 995
Kopano-Meet blocks any further updates

Any idea?

Hi @Hans,

the max message size in Postfix is only part of the solution here, what you are running into is most likely memory limits within php (you could verify this when looking at the error log of the Apache webserver on UCS). The reason why it works with WebApp is because WebApp brings a .htaccess file that overrides the defaults.

You need to adapt your php configuration to use the following values:

        php_value post_max_size 31M
        php_value upload_max_filesize 30M

I have found the error. I use an apache reverse proxy and just added
SSLRenegBufferSize 100000000 in the <Location /Microsoft-Server-ActiveSync> part