created vm on azure with public opened rdp- working ok-but after a day rdp no longer accessible

Hi 365 Admin,

Did you carried out the standard troubleshooting to check the NSG rules and local internet, also router firewall if RDP is allowed or setting some policies?

Please have a look at the troubleshooting guide this has assisted me few times so hope this helps you.

https://learn.microsoft.com/en-us/troubleshoot/azure/virtual-machines/windows/troubleshoot-rdp-connection

Hope this helps.

JS

==

Please Accept the answer if the information helped you. This will help us and others in the community as well.

Hello 365keaAdmin

it sounds like you're having a frustrating issue with RDP access to your Azure VM. Since the RDP was working initially and then stopped after a day, there are several potential reasons this can happen. Here are some troubleshooting steps you can try:

• Check if Windows Firewall is blocking RDP

Use Run Command in Azure Portal (this works even when RDP is down):

Portal → VM → Run Command → RunPowerShellScript

Get-NetFirewallRule -DisplayGroup "Remote Desktop"

If rules show Disabled or Block, fix it:

Enable
Set

• Reset the built‑in RDP configuration

netsh advfirewall firewall set rule group="remote desktop" new enable=yes
netsh advfirewall set currentprofile state on

• Reset the NIC inside the VM

ipconfig
ipconfig
ipconfig

Restart the NIC:

Restart-NetAdapter -Name "Ethernet"

• Verify NSG is not auto‑modified

Go to: Portal → NIC → Effective security rules

Check if there is a rule coming from:

• Azure Security Center
• Firewall Manager
• Policy Assignment

If you see unexpected deny rules remove or exclude the policy.****

• Turn off any Security Baseline or GPO applied by Azure AD / Intune
  Some baselines disable RDP after first sync.

Check: Portal → Endpoint Manager → Devices → Configuration Profiles

Disable any Windows Security Baseline temporarily.

• Enable Boot Diagnostics Screenshot

Portal → VM → Boot diagnostics

If the screenshot shows: “Network Level Authentication error”, this is related to TLS or certificate trust.

reg add "HKLM\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp" /v UserAuthentication /t REG_DWORD /d 0 /f

The reason RDP works on the first day but not after 24 hours is because something inside the Windows OS is changing — usually the Windows Firewall or a security policy — which begins blocking port 3389. Since Azure Bastion also fails, the issue is inside the VM and not related to public IP or NSG. We can resolve this by re‑enabling the RDP firewall rules and verifying that no policy or security baseline is disabling RDP after the machine is running

References:
https://learn.microsoft.com/en-us/troubleshoot/azure/virtual-machines/windows/troubleshoot-rdp-connection