Many users started seeing similar error messages, including one that says, “The application you have selected does not exist.†MacRumors reported that some other Apple services, like Apple Pay and the company’s web-based app-specific password generator, were also experiencing issues, although Apple never acknowledged as much on its system status page.
As of 8:30PM ET, Apple’s system status page says the issues affecting iCloud have been resolved
Update June 2nd, 8:40PM ET: Added that Apple’s system status page says the issues with iCloud are now resolved