The content in the 'Salesforce Connector Requires Attention' email sent by Act-On is verbiage that comes directly from Salesforce.
Act-On relays the error message to its users whenever there is a failed API call attempt so that they can check the connection.
In addition to the reasons listed in the automated email, there may also be several other causes, including:
Check here to see if there is a current Salesforce service incident.
Salesforce usually performs general maintenance activities over the weekend, so this email is more likely during that time. Act-On continues to complete any pending jobs during that time so that when maintenance is complete we are able to run all pending jobs and no action is required from you.
API call limit
If you have several installed packages that utilize APIs, you can check the number of API requests sent in the last 24 hours in your Salesforce account by clicking Your Name > Setup > Company Profile > Company Information. Look for the API Requests, Last 24 Hours field in the right-hand column.
There may be other circumstances in which the connector may not connect successfully to Salesforce; however, the reasons listed in the email along with the three causes above are the primary reasons. Temporary failures not involving password or security token changes do not require action from you. The connection will be re-established the next time an API call is made and Act-On will complete the pending jobs.
For additional information from Salesforce that may be helpful in better understanding API call limits and monitoring, click here.