Solution of Postfix error “mailbox_size_limit is smaller than message_size_limit”

I noticed somehow in the logs the following error:

postfix/local[32288]: fatal: main.cf configuration error: mailbox_size_limit is smaller than message_size_limit

And remembered that I recently increased the parameter message_size_limit in the configuration file /etc/postfix/main.cf, which specifies in bytes the maximum size of messages sent and received.
The error occurs because the value of the message_size_limit parameter is greater than the value of mailbox_size_limit, and it should be the reverse, by the way virtual_mailbox_limit is not specified in the configuration file, apparently if it is not specified, then the standard value is 51200000, which in my case was less message_size_limit.

Let’s look at the value specified in the configuration file mailbox_size_limit and virtual_mailbox_limit (-d shows the standard value):

postconf -n | grep mailbox_size_limit
postconf -d | grep mailbox_size_limit
postconf -n | grep virtual_mailbox_limit
postconf -d | grep virtual_mailbox_limit

Let’s look at the value of message_size_limit:

postconf -n | grep message_size_limit
postconf -d | grep message_size_limit

Let’s manually specify the values mailbox_size_limit and virtual_mailbox_limit manually in /etc/postfix/main.cf so that they are greater than message_size_limit, or by adding the following commands to the file:

sudo postconf -e 'mailbox_size_limit = 102400000'
sudo postconf -e 'virtual_mailbox_limit = 102400000'

Alternatively, you can disable the limit altogether by specifying 0:

postconf -e 'mailbox_size_limit = 0'
postconf -e 'virtual_mailbox_limit = 0'

Restart Postfix to apply the changes:

sudo /etc/init.d/postfix restart

Done, the error should not be.

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