Kendra Box Connector failing

Hello,

We are running a PoC with Kendra and attempting to have Kendra index a large collection of documents in a Box folder. There are multiple levels of folders.

The connector is the one provided and was configured according the guide. A new role was created for access by Kendra as advised.

The crawling takes about 4.5 hours and then fails on the index step. No error messages are written to the CloudWatch logs other than:

{ "GroupId": null, "HashedGroupId": null, "IndexId": null, "PrincipalSourceId": null, "DataSourceId": null, "PrincipalSourceSyncExecutionId": null, "ErrorMessage": null, "ErrorCode": null }

The Box app is properly configured and use of the same credentials in a stand-alone app allows access to all folders and to download.

We are really stuck on how to proceed.

Thank you