Hi Yasser,
Any updates on this issue? Please run the command Ed Crowley provided to check your server role.
If you want to test the autodiscover service for your client users, we can consider to use the Microsoft Remote Connectivity Analyzer tool to do it:
https://testconnectivity.microsoft.com/
Additionally, we can run Test E-mail AutoConfiguration tool in client side:
Open Outlook - press CTRL key - right click on the Outlook icon from right bottom corner taskbar - Test Email AutoConfiguration. Put your email address - uncheck use guessmart and secure guessmart authentication - click Test to check your Autodiscover service.
Regards,