Intermittent connection errors on PHP

Hello community,

I hope someone will be able to help me debug some connection errors in our PHP application.

Our connection between PHP and MongoDB is working fine most of the time. However, some requests fail with either the following error messages:

  • No suitable servers found (serverSelectionTryOnce set): [socket timeout calling ismaster on ‘:27017’]
  • No servers yet eligible for rescan

I have found multiple mentions of these errors online, but they all deal with situations where every requests fails. I haven’t found a reason yet why most requests would work normally, but some fail.

Our environment:

  • Mongo server 4.4 (single instance, no cluster)
  • Mongo PHP driver 1.8.2
  • Mongo PHP library 1.8.0

What can I do to debug this issue?