@Raiffy Sampaio I'm glad that you were able to resolve your issue and thank you for posting your solution so that others experiencing the same thing can easily reference this!
Since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others ", I'll repost your solution in case you'd like to "Accept " the answer. Accepted answers show up at the top, resulting in improved discoverability for others.
Issue: How to fix RDP error 0x204 on Windows Server 2008 R2 Azure VM?
Solution: Customer shared - "After another VM restart, the RDP started working again. One thing that may have interfered was that the Remote Desktop - RemoteFX on the firewall was disabled before."
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