Some programs detect when you have jailbroken your phone, and will refuse to run.

First, try to get a program from Cydia called "Liberty Lite", and that might do the trick.

However, some programs are written really well to detect the jailbreak at the kernel level, so Liberty Lite (and similar programs) will not work.

Here's how to install a very effective jailbreak detection bypass called KernBypass. It requires an already-jailbroken phone with iOS 12.0 or higher.

*** MAKE SURE YOU DO EXACTLY AS LISTED BELOW -- IF YOU SCREW UP, DON'T BLAME ME ***

1) Prerequisites: Filza and Newterm (terminal program). Install both of these from Cydia first. Delete any apps which you want to jailbreak detect bypass.

2) Use your iPhone to click on this link to download KernBypass

3) Once downoad, click "Open in Filza"

4) In Filza, click on the file called jp.akusio.kernbypass_0.0.3_iphoneos-arm.deb

5) On the top right, click Install

6) Close Filza and go to Newterm

7) At the terminal prompt, type: su

8) When it asks for the password, type: alpine
** NOTE ** If you changed your root password, type that instead of "alpine"

9) Type: changerootfs &
** NOTE ** Don't forget the & at the end

10) Hit enter one more time. Then type: disown %1

11) Download apps again which you want to jailbreak bypass

12) Close Newterm. Go to Settings -> KernBypass -> Enabled Applications -> (select the applications you want to bypass jailbreak detection)

13) Make sure you DISABLE Liberty Lite or other jailbreak bypass applications -- at least for the ones which you couldn't get working before -- or this method won't work!

That's it!

If you reboot, redo steps 6-10.