Why won't 'usb debugging' mode stay on? I'm trying to put my phone into usb debugging mode, but it won't work. I'll turn it on, and it will turn off right away.. Has anyone else gone through this?

I'm running 2.3.4 on a zte score.
I had a similar issue with Huawei P Smart (today on Android Oreo).  Revoking USB debug permissions enabling USB debugging and then re-attaching it with 'transfer files' option, followed by accepting the PC certificate fingerprint appeared to work - at least for the time being.