Issue
You have edited a Field or Object definition in Salesforce and are now getting errors in Heroku Connect that indicate that your Mapping is out-of-date. You would like to have the changes made in Salesforce be reflected automatically in your database.
Resolution
Connect doesn't automatically bring changes made to Fields or Objects in Salesforce, into the database as it is unable to determine what impact such a change might have on your running application. Instead, Connect will halt syncing for that Mapping and allow your other mappings to continue syncing as usual while you resolve the issue.
To resolve this, visit the edit page for the mapping in question. Doing so will reveal the newly changed Field(s) from Salesforce and you will be able to check or uncheck the Sync checkbox to remove or add fields as nessesary. Once you click Save Connect will adjust your DB tables to match you selected configuration. Once this completes the error will be cleared and sync will resume.