This error occurs when HubSpot is unable to save data to Salesforce. Next to your Salesforce save error in HubSpot, you will see data from Salesforce that indicates what caused the save error. For example, you might be unable to save a contact to Salesforce because of an invalid email address or if a custom validation rule has been set up for a field in Salesforce.
To fix this you may need to review any validation or restrictions set up in Salesforce and then click the Retry syncing contacts button.
If the issue persists, please contact our Support team.