Munin server service monitoring tool has a strange problem, that the Exim Mail Throughput graph may suddenly stop updating and become blank. The Exim Mail Throughput graph provides useful information and statistics on how many mails have been received, completed and rejected per second.

The exim_mailstats graph initially work properly, and then stop workin, with no update on graph. In the munin-node.log file, the following error can be found:

Plugin "exim_mailstats" exited with status 768. ----

The error cause is probably due to the plugin state is not reset or tracked properly. To fix and solve the problem Exim Mail Throughput graph stops updating, simply rename or delete the plugin-exim_mailstats.state file located in /var/lib/munin/plugin-state/ directory. It’s best to rename the file to another name first, and verify that the graph is updating again before proceeding to delete the old state file away.