When sending a message, you may see a red box at the top of the screen with a message warning of:
Warning. You have at least one endpoint offline. Please double-check that necessary endpoints are active and online before clicking send.
As you may surmise, this warning is there to let you know that one (or more) of your Endpoints isn't reachable or isn't properly configured. When Omnilert checked, something didn't look right.
How to tell which endpoint has a problem
You can see which endpoint isn't working right by scrolling down to the "Select how" section. The offending endpoint will be disabled and show a red circle next to its status.
Why is an endpoint ever offline?
The exact reason why a specific endpoint isn't working can vary based on the endpoint. For example, you may need to enter credentials or a server address into the configuration for that endpoint.
It's possible that an external server is down or unreachable due to a local outage in your area or with that third-party vendor. (In some cases, such as a local power outage, some local endpoints might be expected to go offline or be unreachable.)
What to do?
Of course, you can still send a message to any of the endpoints with a green, solid circle. (Those are the ones that are online and configured!)
To correct the problem, go to the Endpoints >> Active list and click on the offending endpoint. Then adjust its settings accordingly.
If the offending endpoint isn't being used at all anymore, you can always make it "Inactive" to remove it from service.