We are facing this issue with our collector which is deployed in Linux box"The Agent is connected, but Instrumentation was disabled during Agent runtime. The Collector runs on low memory."
Note - we use same server for collector and server, memory utilization looks under control.
Have you checked the memory of the host itself or of the collector process. You can look at your deployment dashboards to see the memory usage of the collector. You may need to make more memory available to the collector process via the .ini file if you're getting memory errors but have plenty available on the host.