Error when creating knowledge base

Getting this error when i tried creating knowledge base

Failed to generate Amazon Opensearch Serverless vector database: Policy json is invalid, error: [$[0].Principal[1]: does not match the regex pattern ^saml/[0-9]{12}/[a-z][a-z0-9-]+/(user|group)/.{1,60}$, $[0].Principal[1]: does not match the regex pattern ^arn:(?:aws|aws-cn|aws-us-gov):iam::\d{12}:(user|role)(/[\w+=,.@-]+)*/[\w+=,.@-]{1,64}$, $[0].Principal[1]: does not match the regex pattern ^arn:(?:aws|aws-cn|aws-us-gov):sts::\d{12}:assumed-role/[\w+=,.@-]{1,64}/([\w+=,.@-]{2,64}|[\w+=,.@-]{0,63}\*)$]

The knowledge base storage configuration provided is invalid... Request failed: [security_exception] all shards failed

Start by reviewing the knowledge base storage configuration and the Amazon OpenSearch Serverless policy named in the error. Check the Principal value against the policy patterns in the report and reproduce knowledge base creation; done means creation succeeds without the invalid-policy or all-shards-failed errors.

Written by the indexing model from the issue text.