Kindly do self troubleshoot as per below and try to relogin after:
1) Logout and re-Login App- if error still persisting proceed to next step
2) Uninstall and re-install App - if error still persisting proceed to next step
3) Restart & update the app
Double-press the Home button and find Touch ‘n Go eWallet app then swipe the app up to close the app. Re-launch Touch ‘n Go eWallet app. Then go to setting -> general -> software update -> update your iOS (as required). Next, go to App Store -> Update
4) Line connectivity
Launch your internet browser, type www.google.com and tap Go. If the page fails to load, you may have internet connectivity issues.