imp needs caller ID in order to screen your calls properly. In the app, if caller ID is unable to be read by the imp box, it will report as "Someone with no Caller ID." You may see this from time to time.
Have no fear, this is perfectly normal. Caller ID is actually made of three bits of information: Name, Number, and Location. How much of that is passed to imp, and then to you, depends on where someone is calling from, what phone they are using, what telephone carrier you are using, what carrier they are using, and the price of rice. Seriously. We scratch our heads on this all the time. What we do know is that imp will pass along all the information it can. And that the information may vary from call to call.
If every call reports as "Someone with no Caller ID" that typically means caller ID has been disabled by your telephone provider. Please contact them and check if that is the case.
If that does not resolve your issue, please tap “submit a request” at the top right of this page.