Credential and Authentication Errors
Use when the VM is reachable but sign-in fails.
Symptoms -> Solutions
| Symptom | OS | Action | Docs |
|---|---|---|---|
| credentials failed, must change password, account expired | Windows | Reset password; extend account if needed | Reset RDP |
| trust relationship failed | Windows | Reset machine account or rejoin domain | RDP overview |
| access denied, connection denied, wrong local/domain format | Windows | Add Remote Desktop Users; use VMNAME\user or DOMAIN\user |
RDP errors |
| CredSSP encryption oracle | Windows | Temporary client workaround; patch both sides | CredSSP |
| permission denied publickey/password | Linux | Verify user/key/password auth; reset key/password if needed | SSH detail |
| locked account | Linux | Unlock via Run Command or Serial Console | SSH overview |
| Entra ID SSH denied | Linux | Assign VM Admin/User Login role | SSH overview |
| sudo prompt fails | Linux | Fix sudoers via Run Command or Serial Console | SSH overview |
Quick Commands
Commands use VM agent/extensions. Run Pre-Flight Safety Checks first.
# Windows password / RDP reset
az vm user update --name <vm> -g <rg> -u <user> -p '<new-password>'
az vm user reset-remote-desktop --name <vm> -g <rg>
# Linux key/password reset or unlock
az vm user update --name <vm> -g <rg> -u <user> --ssh-key-value "<ssh-public-key>"
az vm user update --name <vm> -g <rg> -u <user> -p '<new-password>'
az vm run-command invoke --name <vm> -g <rg> --command-id RunShellScript --scripts "passwd -u <user>"