Hello DaminiNUU,
Ensure that your Microsoft 365 E5 license is properly assigned to your account. You can check this by the Microsoft 365 Admin Center:
https://www.microsoft.com/en-us/microsoft-365/b...
Log in first to your account, and under Users > Active users. Kindly confirm that your account is listed and has the E5 license assigned.
After that, I recommend you use the Activation Troubleshooter: Go to Settings > System > Activation and click on Troubleshoot. This can help identify and resolve any activation issues.
If the issue persists, try this temporary workaround. Temporarily enter a generic Windows 11 Enterprise key to prompt the system to upgrade. Go to Settings > System > Activation > Change product key.
Enter the generic key for Win 11 Enterprise: XGVPP-NMH47-7TTHJ-W3FW7-8HV2C
This may trigger the upgrade process, but you'll still need a valid product key to fully activate Windows 11 Enterprise later.
Let me know if you have any other questions or need further assistance with this.