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KnownCalls, call blocker: Troubleshooting common issues

The application for blocking “uninvited” calls KnownCalls is easy to set up and works in a variety of conditions with phones from diverse manufacturers, brands and with different versions of the Android operating system. In rare cases, users may face problems while choosing the right settings for the application or getting acquainted with its functioning. We have prepared several visual instructions on what to do if KnownCalls does not work, does not block some unwanted calls, or blocks even necessary calls.

First, let’s look at the case of “What to do if KnownCalls doesn’t work“. Although “doesn’t work” is a rather vague wording, since KnownCalls’ work is primarily to block calls, here we assume that it means that KnownCalls does not block calls from unknown numbers at all. In this case, it is recommended to check the settings: whether blocking is enabled and whether the application is given the necessary rights to do its job. The app status should be “Active”:


Next, let’s consider the case that users describe as “Mostly it works well, but sometimes unnecessary calls still come through.” Here we would like to immediately point out that no random omissions are supposed to happen in the KnownCalls app, unlike those that rely on spam databases for their work. The operating mechanism of our app (comparing the calling number with the Contacts or Favorites list) does not require Internet access, so it should work quickly and without failures. We also note that the logic of this work is precisely to allow only authorized numbers to pass through, and everything else – unknown numbers and any controversial options – will be blocked by the application. There cannot be a situation where KnownCalls periodically skips unfamiliar numbers because it cannot decide whether to block them or not: everything not from the lists should be blocked. So, missing some unknown numbers when blocking is enabled is only possible if the application was not working at the time such a call was “received” (to make sure that it wasn’t functioning, you can look at the Call Log: there will be no record of such a missed call). If the problem is confirmed, then it is unlikely that this can be solved on your side, but first of all it is worth carrying out a diagnosis according to the picture below. Still, the most important advice in this situation is to check out if a newer version of the application is available. The troubles can already be dealt with there.

If this is your case, see our graphical step-by-step instructions below:


Let’s also consider a situation where the KnownCalls blocks calls even from numbers in Contacts. In this case, it is recommended not only to check if a newer version of the application that may already resolve this issue is available, but also to ensure that the settings are correct. There are a few more important tips to solve this issue with unwanted blocking in KnownCalls, see them in the step-by-step instructions below:

So, we’ve looked at the potential blocking issues in the KnownCalls app and how to deal with them. In conclusion, we would like to provide a summary flowchart for solving problems and questions regarding the app for blocking unwanted calls KnownCalls:


We hope that the above instructions can help you to resolve issues where KnownCalls blocking is not working or not working the way you want. If you have more questions, you can ask them on our forum and get answers from the KnownCalls community.

May 15, 2024

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How to set up the KnownCalls app: SMS filtering, call blocking, permissions
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