Invite Link Delivery Delay

My friend added me about 10 hours ago (iPhone) using my invite link (chatmail server) while my phone was off. I turned my phone on a few hours later, but I haven’t received any notification about the new contact.
How many more hours should I wait for the connection to be established?

Establishing a contact using QR code takes two round trips:

  1. You friend scans a QR code and sends you first message.
  2. Your device receives first message and responds.
  3. Your friend’s device receives your device response and sends a second message.
  4. Your device receives the second message and displays a new chat.

So it might be that the process is currently stuck at step 3 because your friend’s phone is not online.