I had a similar issue, that was resolved by assigning storage credential to the metastore using REST API call.
- make sure that you are metastore or account admin
- make sure that the storage credential is correctly configured, its access corrector identity has the right level of privileges on the storage account
- run the PATCH rest statement:
Update a metastore | Metastores API | REST API reference | Azure Databricks
/api/2.1/unity-catalog/metastores/{id}

{
  "storage_root_credential_id": "id_string",
}