Intermittently, Import Jobs and Data Links from Salesforce will fail with the following error:
ErrorLogException: Failed to read record source, byte position is 500
Caused by: datameer.webservice.WebServiceResponseException: Failed to open '<Salesforce Query URL>' Bad Request (400): invalid query locator
This issue is due to limitations on the number of queries allowed by Salesforce. Currently they have a hardcoded limit of 10 queries every 15 minutes. Exceeding 10 queries within 15 minutes will result in this error.
Exact details of the limitation can be found on Salesforce's website - Error: Invalid Query Locator
Limit the number of queries against the Salesforce API to 10 every 15 minutes by scheduling job runs with sufficient time between them.