Quite often, players encounter various errors, with a certain encoding that requires decryption.
Specifically, error 15035 occurs due to account blocking. This happens if you played through an emulator or used third-party software to gain an advantage over your opponent.
Now they have created very actively ban accounts for using emulators. Many even get several bans in a row and they don’t understand why. You can read more here — Are they banned for using the emulator in Call of Duty Mobile.