Hi @Jerry George R Thank you for posting your query on Microsoft Q&A and for using Azure services.
As mentioned above you are trying to upgrade your Azure flexible server from 5.7 to 8.0.
If you'd like to upgrade from 5.7 to 8.0, we recommend you perform dump and restore to a server that was created with the new engine version.
Let me know if you need further help with the dump and restore
Regards,
Oury