The verification loop
You enter the code, the app thinks, and you are back at the start. First, check the basics: the code expires fast, so request a fresh one and enter it within a minute. If it still loops, force-stop TikTok Mod Cloud, clear cache (not data), and try once more. The loop is usually a stale session token, and the cache clear is what evicts it.
Stuck on the sign-in screen
If the sign-in page itself never loads, your TikTok Mod Cloud app cannot reach TikTok's servers cleanly. Toggle airplane mode on for ten seconds and off again to reset the connection, then retry. Date and time set wrong on the phone also breaks logins silently: set them to automatic in system settings. This sounds unrelated until it fixes your problem.
Try the other network
Some Wi-Fi networks and some carriers filter TikTok traffic in ways that break login but not browsing. If login fails on Wi-Fi, try mobile data, and vice versa. This is also where the region unlock notes matter: accounts tied to heavily filtered regions log in more reliably on the network that filters less.
When to reinstall the login
If nothing works, uninstall and install the current build fresh from TikTok Mod Cloud APK, then log in before restoring anything else. A surprising number of login ghosts are just a bad first install. Your follows and likes are server-side and return the moment you sign back in.
