Roundcube attachement size

When I login to

server/webmail

I am able to attach big files

For same email id, if I login to

domain/webmail

I get connection error while attaching big files (same files which works in above case)

Please suggest

PHP directives "upload_max_filesize" & "post_max_size" largely control this, but also postfix's message size in /etc/postfix/main.cf must also agree.

Thanks a ton.

This can be actually a good article.