Sideloading question (iOS): How to fix 'integrity could not be verified"?

Question

trying to sideload onto my iphone, but cant get anything to install. i keep getting things along the lines of "could not be installed because the app's integrity cannot be verified". can someone tell me how to fix this? ** remember: i am not using testflight or anything hence this because nobody has reported this issue as a developer. this is just simple sideloading for personal use **

tried to sideload ipa, worked (appears on the home screen), but doesnt install upon tapping it.