Hi MSM,
Thank you for reaching out to us on Microsoft Q&A forum.
Please click on the link as provided in the below screenshot.
Upon clicking the link, you will be directed to the below screenshot provided page.
Please try to use a work or school email address to sign up.
Upon submission of the work email address, you may proceed with commencing the process to practice the Dynamics 365 Business central.
In the Environment Type list, choose Sandbox. The new environment won't be accessible until the State shows Active.
Note: Business Central doesn't support email addresses that are provided by consumer email services or telecommunication providers such as outlook.com, hotmail.com, gmail.com, and others.
If you try to sign up with a personal email address, you'll receive a message indicating that you need to use a work or school email address.
Please try to use a work or school email address to sign up.
If you are still facing any issue, please let us know in the comments. We are glad to help you.
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Thank you.