Titanium is not updated since years. Give Neo Backup (former OAndBackupX → initially a OAndBackup fork) a try. I really like it and can recommend it. I moved my stuff from A10 to A11 (LOS) and now to A12 (CalyxOS) with it successfully.
→ start reading the FAQ FAQ first 
e.g. What is the difference to the famous Titanium Backup?