Hello @Brad Zuercher
Thank you for Reaching Out Microsoft Q&A Platform.
I understand that you are experiencing an issue with your Microsoft 365 admin account, where your admin access has disappeared. When trying to access any Microsoft 365 products, you are receiving the error message "Error 135011".
To hopefully help point you in the right direction, I found the related troubleshooting documentation for your error code. This issue can occur if the device was either deleted or disabled in Microsoft Entra ID, and the action was not initiated for the device itself.
As you mentioned that your Microsoft 365 admin access has disappeared, I suggest navigating to Entra ID > Users > Roles and Administrators to verify whether you still have admin access. Please check your assigned roles to confirm if your admin privileges are still active.
To resolve the issue, you can follow the steps below:
- If the device was disabled in Microsoft Entra ID, an administrator who has sufficient privileges can re-enable it from the Microsoft Entra admin center, as follows:
- Sign in to the Azure portal.
- Select Microsoft Entra ID > Devices.
- Examine the disabled devices list in Devices, by searching on the device name.
- Select the device, and then select Enable. For more information, see Manage device identities using the Azure portal.
If the device was deleted in Microsoft Entra ID, you have to re-register it manually. For detailed steps to do this, see Re-enable or re-register the device.
Do let us know if you any further queries.