The 500 (-200) error typically appears when a user tries to check in a change to a table and that table's upload step is checked out in another workspace.
The majority of the time this happens when Datalink uploads new data to a table and is either in the process of checking in the upload OR the upload failed validation and needs manual intervention to validate the change and check in or revert the change, fix the data and then re-run the connector.
If you see this error, you will want to click on the environment selection drop-down and look for a datalink workspace "In Development(dl_svc_main@DomainName.com)" If you see one, you will want to check in or revert the uploads that failed validation before you will be able to check in the changes to that table in your workspace.
If you don't have a datalink workspace in the environment drop-down list, you will want to open a support case to get this issue investigated and resolved.