My messages are sending but I'm not recieving them for a couple minutes. Whats wrong?

[Android Central Question]

I sent someone a message and they got it, but when the messages me, I didn't get it for 5ish minutes. I have a Galaxy S9, they have a Galaxy Note 8. I believe it has to do with the MMS/SMS thing.

 

[ManiacJoe]

The communication chain looks something like this:
sender's phone > sender's carrier cel network > sender's carrier server > internet > receiver's carrier server > receiver's carrier cel network > receiver's phone

Lots of places there for a slow down to happen. If you are both on the same carrier, it does get optimized a little.
Which carriers are you two using?
Do you both have strong phone signals?

If you both turn on your delivery receipts, how quickly do they light up?