ResolutionBy default, PHP limits uploaded files' size to 2 MB. This limit applies to all PHP applications including Webmail. Edit the following options in the "/etc/php.ini" file on the Plesk server and set the values to match your needs. For example:
upload_max_filesize = 32M
post_max_size = 32M
Restart Apache after the "php.ini" file modification.
Also note that the maximum attached file size can be changed by adjusting the Horde configuration. Find the "attach_size_limit" option in the "/etc/psa-horde/imp/conf.php":
$conf['compose']['attach_size_limit'] = '0';
An "attach_size_limit" value of zero means "no limit."
Additional informationNote that "memory_limit" should be larger than "post_max_size."
If you increase the" post_max_size" PHP parameter, do not forget to increase the "memory_limit" parameter also.
According to Description of core php.ini directives:
sets max size of post data allowed. This setting also affects file upload. To upload large files, this value must be larger than "upload_max_filesize." If memory limit is enabled by your configure script, "memory_limit" also affects file uploading. Generally speaking, "memory_limit" should be larger than "post_max_size." When an integer is used, the value is measured in bytes. Shorthand notation, as described in this FAQ, may also be used. If the size of post data is greater than "post_max_size," the"$_POST" and "$_FILES" superglobals are empty. This can be tracked in various ways, e.g., by passing the "$_GET" variable to the script processing the data, i.e., <form action="edit.php?processed=1">, and then checking if $_GET['processed'] is set.
Note: PHP allows shortcuts for bit values, including K (kilo), M (mega) and G (giga). PHP will do the conversions automatically if you use any of these. Be careful not to exceed the 32 bit signed integer limit (if you're using the 32bit version) as this will cause your script to fail.