Today, I have created a Whatsapp group and accidentally left the group. Now the present admin of the group is not able to add me back. Kindly suggest me what to do.
You can't delete a WhatsApp group unless you're the last person leaving it. If your friend's phone is throwing an error, try getting him to make another member of the group an admin, and then the second admin could try adding you. But deleting the group without it being completely devoid of members is impossible.