Go to your iPhone's Settings app (the gray gear icon).
Scroll down and tap on "Telegram".
Toggle the switch next to "Contacts" to ON.
Internet Connection: A stable internet connection (Wi-Fi or mobile data) is essential for syncing. Test your connection by trying to open other apps or websites.
Restart Telegram App: Fully close the Telegram app (swipe it away from recent apps) and then reopen it. This can often resolve minor glitches.
Restart Your Device: A full device restart can clear temporary software bugs that might be interfering with app functions.
2. Deeper Troubleshooting Steps
Delete Synced Contacts and Re-sync: This is often a telegram number database highly effective solution as it forces Telegram to start the sync process from scratch.
Open Telegram.
Go to Settings > Privacy and Security > Contacts.
Toggle "Sync Contacts" OFF.
Restart the Telegram app (close and reopen).
Go back to Settings > Privacy and Security > Contacts.
Toggle "Sync Contacts" ON again.
Wait a few minutes for the re-sync to complete.
Clear Telegram Cache: Corrupted cache data can sometimes cause sync issues.
Open Telegram.
Go to Settings > Data and Storage > Storage Usage.
Tap "Clear Telegram Cache" (or similar option depending on OS). Confirm the action.
Restart the app.
Update Telegram App: Ensure you're running the latest version of Telegram. Bugs in older versions can sometimes cause sync problems.
Go to your device's app store (Google Play Store for Android, App Store for iOS).