Micorosft released a security update this May that patched an RDP vulnerability.
However, if your client machines updates before your VPS does, you could lose RDP access.
If your VPS is affected, You might see an error that reads:
"An Authentication error has occurred. The function requested is not supported. This could be due to CredSSP encryption oracle remediation."
Contact our support and we will help remedy the situation. But, we recommend updating your VPS immediatley, before your client machines do.