Same here!

2nd day, same problem...Today morning (GMT +1) working fine for few hours, and than again same problem...I was able to update to the latest version on TestFlight without any problem. After that, same scenario again, "App cannot be installed..." Still waiting for Apple to resolve issue, meanwhile my client that wanna test the changes that i made in the app's are angrier and angrier... Do i need to mention that client = founding = money (in this case loosing the same) ???

Same here, all apps that are on TestFlight fails to install/update. Only grayed icon with cloud download, and in TestFlight app install option again, when i try to run "installed app" say: " Unable to Install . This app cannot be installed because its integrity could not be verified." Tried every possible thing and solution, build xy number of builds again and again. Still the same problem. Apple do something!!!