I am using terraform cloud enterprise
It errors out while making a plan
2021-04-02T04:04:38.570Z [WARN] plugin.stdio: received EOF, stopping recv loop: err="rpc error: code = Unavailable desc = transport is closing"
Error: timeout while waiting for plugin to start
The error alone is unfortunately not enough to diagnose the issue, but it indicates that the plugin process, i.e. the provider, did not initialize before the timeout (which IIRC is 1 minute by default).
This is usually caused by some system limitation, most commonly insufficient CPU, memory , or an environment lacking a suitable source of randomness for generating the TLS keys.