Timeouts will occur from time to time due to the nature of real-time verification. These are only an issue if they occur frequently or with larger email providers such as Gmail, Yahoo and the like. You can adjust the timeout with the timeout setting if this is happening too frequently or if the default timeout is too long.
This will occur when you no longer have credits in your account. You can purchase additional credits within the dashboard or switch to monthly billing to avoid the issue altogether.
A bad referrer means the domain in which the widget is being used on is not authorized to use it. This is controlled from the “Trusted Domains” section within the widgets settings through the dashboard.
Throttling is a protection method to curb and prevent abuse of your forms. This can be adjusted in the “Throttling” section of the widgets settings within the dashboard.