CloudFormation failed to recognise OpenSearchServerless

The following documentation shows that the resource type itself is supported, so we would like to check the template. I would also like to see if the same event occurs using the same region as yours. https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/AWS_OpenSearchServerless.html

London region, Step 2 in here has the template (https://catalog.us-east-1.prod.workshops.aws/workshops/f8d2c175-634d-4c5d-94cb-d83bbc656c6a/en-US/20-getting-started/02-aws-owner-account/02-01-bootstrap)

Now, you make me wonder regarding the Region. It seems to be working in us-east-1

The following documentation shows that the OpenSearchServerless API is not yet supported in the London Region. In other words, it is not possible to create them in the London Region, either through CloudFormation or the Management Console. https://docs.aws.amazon.com/general/latest/gr/opensearch-service.html OpenSearchServerless is currently available only in the following regions.

US East (Ohio) us-east-2
US East (N. Virginia) us-east-1
US West (Oregon) us-west-2
Asia Pacific (Singapore) ap-southeast-1
Asia Pacific (Sydney) ap-southeast-2
Asia Pacific (Tokyo) ap-northeast-1
Europe (Frankfurt) eu-central-1
Europe (Ireland) eu-west-1