If a person has left the group in the past, you need to be in their Telegram contacts to add them back.
They can still join via an invite link as long as they are not on the group's invite link as long as they are not on the Removed Users list.
194
Sorry, this user decided to leave this ቡድን, so you cannot invite them back here.
80/194
Moti,
Dec 14, 2018 at 14:15