Hello,
If this issue is related to mails not coming when the attachment is very big, this can be caused by settings in
php.ini. Please try to set up the following to these large values:
post_max_size = 256M
upload_max_filesize = 500M
max_input_time = 240
max_execution_time = 500
max_input_vars = 4000
memory_limit = 128M
If you don't have access to your php.ini file, contact your hosting provider as they could do it for you.
After you do so, please restart the server and test whether something changes.
Regards,
Mihaela
