Horde shows the size of the message you are trying to send exceeds a temporary size limit of the server

My current email client is Horde webmail and today, I tried to simply respond to a message sent to me a couple of days ago.

The message delivery fails with the following message:

For Solution: Open /etc/exim.conf file and change the message size limit according to your choice.

#!!# cPanel Exim 4 Config

disable_ipv6 = true
message_size_limit = 20M
smtp_accept_queue_per_connection = 50

hostlist loopback = <; 127.0.0.0/8 ; 0.0.0.0 ; ::1 ; 0000:0000:0000:0000:0000:ffff:7f00:0000/8

hostlist senderverifybypass_hosts = net-iplsearch;/etc/senderverifybypasshosts

hostlist skipsmtpcheck_hosts = net-iplsearch;/etc/skipsmtpcheckhosts

hostlist spammeripblocks = net-iplsearch;/etc/spammeripblocks

hostlist backupmx_hosts = lsearch;/etc/backupmxhosts

hostlist trustedmailhosts = lsearch;/etc/trustedmailhosts

hostlist relay_hosts = net-iplsearch;/etc/relayhosts

domainlist user_domains = ${if exists{/etc/userdomains} {lsearch;/etc/userdomains} fail}

remote_max_parallel = 10

smtp_receive_timeout = 165s

ignore_bounce_errors_after = 1d

rfc1413_query_timeout = 0s

timeout_frozen_after = 5d

auto_thaw = 7d

Then save and exit, That’s it.

On the off chance that still you are facing the same issues, try to disable firewall (CSF and APF) and check it.

If still facing issue after disabling firewall, try to reset the Exim configuration via WHM panel and try to access it, Definitely it will resolve your issue (Make sure, While resetting the Exim configuration you will lose your all manual configuration).