Uncover Jailbreak Error something OTA???

[JohnMillionaire]

It obviously is compatible as the button wouldn’t be available to click

Also my iOS is 12.1

iPhone XS Max

 

[1Icarus2]

iOS 12 Cydia and Substrate are not supported on A12-A12X as of yet.

Also, check if OTA updates have downloaded a file in your Storage. If it is there, delete it first.

 

[TriJetHero]

Remove the OTA download and try again, if that does not work, make a backup, reset all settings and content and restore backup, try again