Hello @Testa ,
There can be multiple reasons why you might face RDP issues to your VM.
There could be some guest OS issues that your VM's OS might be running into. I would recommend you to check the Remote Desktop Event viewer logs.
Also, could you specify how is the network configured for the VM? Does your VM have a public IP?
Also, there could be issues with the performance of the VM as well. Sometimes, when the VM is running at its full capacity in terms of memory(RAM), it may stop accepting any new connections for RDP or any other purpose, because it doesn't have enough memory to service those connections.
The list can go on and on , but to actually understand and pinpoint on what is causing the issue, please provide us some initial log to understand and provide you with a probable cause. Thanks.