[Question] I can't install sideloaded apps anymore

I’ve downloaded a bunch of stores like Tutuapp and Appvalley, and through them I’ve downloaded some apps likes Snapchat++ and some other apps

They were working fine for about a week, today however when I click on an app I get the following error message: “Unable to verify app, an internet connection is required to verify trust of the developer” (internet connection required? I'm already connected to the internet!)

So I uninstalled tutuapp, the apps I installed through it and decided to do a fresh install. However this time when I re-downloaded Tutu app, an error message showed up: “Unable to download app, Tutu regular version could not be downloaded at this time".

Since it’s been a week the app got revoked I believe, but shouldn’t deleting and reinstalling solve the issue? I disabled the automatic timing and set the date to 3 days back, this didn't solve the issue as well.

I just installed Antilock and visited ocsp.apple.com to make sure it’s working and it is. Although the app developers said that this method was patched by apple when I first opened the antilock app. Anyway, I believe I should have done this step before the apps revoked? Another apps that i wanted to install

Not sure what to do, please help