Could you please share a bit more about your issue?
Do you mean that the error message would show up when click Pin to Home" option within PowerApps Mobile App in your Mobile device?
Further, which mobile device do you use? iOS device or Android device?
I have made a test on my side (on my iOS device, the version of iOS device is 12.1.4), and don't have the issue that you mentioned. Based on the error message that you mentioned, I suppose that you do not enable Notification functionality for PowerApps Mobile App in your mobile device.
Please check if you have enabled the Notification functionality for PowerApps Mobile App in your mobile device. If not, please enable this functionality for PowerApps Mobile App in your mobile device, then check if the issue is solved.
More details about enabling notification functionality for app in your mobile device, please check the following article:
In addition, please also check if the version of your Mobile device is the latest version, if not, please consider take a try to upgrade it to the latest version, then try it again, check if the issue is solved.
Community Support Team _ Kris Dai If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.