Workspace Android App doesn't work for: https://corpws-umbrella....

Yes. There is a clearly defined cause for this error on the Amazon WorkSpaces side. Given the situation you described, rather than looking at the Windows image itself or RDP issues, it is best to first check the "Access control" settings for the WorkSpaces Directory.

Official AWS troubleshooting documentation cites the following cause for this specific error: ([AWS Documentation][1])

“This device is not authorized to access the WorkSpace. Please contact your administrator for assistance.”

Three points to check first

1. Is Android permitted to access WorkSpaces?

In the WorkSpaces console, please check:

Directories → Target Directory → Other platforms

If the device type you are using—in this case, Android—is not permitted, this error will occur. AWS explicitly lists "the device type being used has not been granted permission to access WorkSpaces" as a cause. ([AWS Documentation][2])

2. Is "Trusted devices" enabled?

Please also check the following setting for the Directory:

Access control options → Trusted devices

If this is set to Trusted devices, the connection from Android may be rejected if the Android device lacks the required client certificate or if the certificate does not meet the necessary criteria. ([AWS Documentation][1])

Conversely, as a temporary troubleshooting step, you can change the setting to Allow all to see if you can connect from the Android device.

3. IP Access Control Group

If an IP access control group is configured for the Directory, please verify whether the global IP address of the network the Android device is connected to is included in the allowlist.

This issue may arise not because the connection is rejected simply because it is Android, but because the source IP address used when connecting from Android differs from the one used for Windows/RDP connections. AWS also lists IP access control as a potential cause for this error. ([AWS Documentation][1])

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Given the current situation:

Access via RDP works 100% without issues Only the Android WorkSpaces app fails

...then, rather than investigating the health of the Windows image or the WorkSpace itself, you should examine client/device access controls at the Directory level.

In particular, I recommend checking in this order:

Android → WorkSpaces Directory → Access Control / Trusted Devices / Other Platforms

Note that AWS documentation indicates you can also capture advanced logs for the Android client. You can enable this in the Android WorkSpaces app by going to Support → Logging settings → Enable advanced logging and then using Extract log to retrieve the log file. This log is useful if you need to request an investigation by AWS Support. ([AWS Documentation][1])

Therefore, while MDM/Android Enterprise could be the cause, there is no need to assume from the start that MDM is the culprit. The first factors AWS lists regarding this error are the WorkSpaces Directory settings for IP access control, Trusted devices, and device type access.

https://docs.aws.amazon.com/workspaces/latest/adminguide/amazon-workspaces-troubleshooting.html?utm_source=chatgpt.com "Troubleshoot issues for WorkSpaces Personal - Amazon WorkSpaces"

https://docs.aws.amazon.com/ja_jp/workspaces/latest/adminguide/amazon-workspaces-troubleshooting.html?utm_source=chatgpt.com

https://repost.aws/articles/ARCg46_zL9S5WUgypbLPr9_g/amazon-workspaces-personal-playbook?utm_source=chatgpt.com "Amazon WorkSpaces Personal Playbook | AWS re:Post"