You need to check injections section may be you have added OneSignal code manually. I suggest to remove it and to add options to the original One Signal integration if you need a bell. UNA and your own code may conflict.
I believe i ran into the same problem using oneSignal. Apparently it cannot start workers on the page.? Onesignal also allows you to add twilio when setting up an app. Not sure if this has caused conflicts with having twilio integrated in una settings and causing twilio to try to load twice.
