SAS keys on the portal has a break compatibility issue with SQL Server
The SAS key generated in Azure Portal has sv=2019-12-12
This sv is not supported by SQL Server credentials to be used for backups to azure storage.
Using Azure CLI we can generate the sv as 2018-11-09 and this sv works with SQL Server.
Using SSMS UI the sv we can generate is 2018-03-28, and it works as well.
In summary: Each tool is providing a different sv, some of these sv's have breaking compatibility features and the portal is not able anymore to generate an sv compatible with SQL Server backups.