It’s worth noting that EC2 spot blocks are being phased out:
Spot Instances with a defined duration (also known as Spot blocks) are no longer available to new customers from July 1, 2021. For customers who have previously used the feature, we will continue to support Spot Instances with a defined duration until December 31, 2022.
Yeah, thanks for the update. I also read in the Document that AWS no longer supports the Spot Blocks from July 1,2021 to the new customers and are available to the existing customers till December 31,2022.