Dear Kalistyan,

We have not tested Xeams behind an HAProxy server and therefore, cannot comment on the intermittent problem you are having. However, reading their website I assume this HAProxy configuration does load balancing between MASTER and CLUSTER Xeams. You should not do that. When using Xeams in Clustered environment, you do not want anyone connecting to the SLAVE's web interface. That is because a SLAVE will never pull any information from the MASTER.

For example, when you search for an email on MASTER, it will pull the results from itself (MASTER) as well as SLAVES. This does not work the other way around. Similarly, if you change any rule on MASTER, it will get pushed to SLAVES. If you change any rule on SLAVE, that will get overwritten by the data pushed from the MASTER.

Therefore, you should NOT run a Xeams cluster through a reverse proxy server that can switch HTTP requests between MASTER and SLAVES