First we will want to verify the connection the Collectors have to the vCenter.
- First go onto the Collector server and verify the service ‘Veeam VMware Collector’ is running
- After that verify the credentials are correct. You can do that by following this link in the user’s guide https://helpcenter.veeam.com/mp/80/vmware_guide/index.html?basic_configuration_launch_web_ui.html
- After this has been verified it may be a good time to analyze if you need to add more collectors. If this error started happening after you added a host or some VM’s then it may be required. Using the install media for Management pack you can run a collector only installation on a server to see If this resolves the issue or you can deploy the collector through SCOM as well.
This link below will help you with the collector only installation.
- https://helpcenter.veeam.com/mp/80/vmware_guide/index.html?collector_only_installation.html
Usually these steps will resolve the issue. The most common solution is having to add additional collectors. If these steps did not work, then please create a ticket with support.