OpenSearch Dashboards Index Pattern and Discover issues

I've loaded 1600+ JSON files via the Bulk API into an OpenSearch domain and have verified that via the Developer Tools console. Now I wanted to use the _dashboards interface to create an index pattern and then use the 'Discover' option to search. I'm following the instructions from here --> https://docs.aws.amazon.com/opensearch-service/latest/developerguide/gsgsearch.html

I am able to successfully create the index pattern, but then when I click on 'Discover', it takes me to the 'Create Index Pattern' screen again. Hopefully there is something trivial that I've overlooked. Thanks.