Hello Stephen!
Thank you for contacting the Microsoft community.
As we understand from your post, you want to check the reason you don't qualify for a Microsoft 365 E5 instant sandbox. We are happy to help you!
Please know that you have reached the Microsoft Credentials Support which covers inquiries and/or concerns related to certifications and exams benefits and requirements found within the Microsoft Certification Dashboard.
At this moment we have verified that your inquiry is not related to your Microsoft's Learn profile. Please note that we don't have access to the Microsoft 365 Developer Plan, as we provide support only for the Microsoft Certification platform.
As much as the Microsoft Certification Program would like to assist you, the Microsoft 365 Customer Service is supporting these issues.
To receive appropriate assistance with your request, we invite you to contact Microsoft 365 Customer Service and Support, so they can verify your access.
With that said, we can only recommend you contact the Microsoft 365 via this link:
Also, please check the following link with the information regarding the Microsoft 365 Sandbox:
If you require assistance with your Certification Profile, please let us know, we will be happy to help.
Please let us know if there is anything else we can do for you. If no additional assistance is required, please indicate “Yes” to the question and the thread will automatically be closed and locked. In case we do not receive a response, it will be closed and locked after one business day.
Best Regards,