Phone not receiving txt messages

[schrodingers cat]

There are 2 phones, both connected to the 2degrees network. Phone A (Galaxy S2) can "send" txt messages to phone B (cheap oldskool Nokia I think), but phone B never receives the messages. However, phone B can send txt messages to phone A, and phone A always receives them. There are no apparent errors when trying to send the message either, but the messages just vanish. Phone reception is not an issue as both phones are located in Christchurch.

Both phones don't seem to have any issues sending/receiving messages to/from other phones. It's just that these 2 phones won't play nice, and it's been happening for a few months now.

Yes. Same problem but both phones on telecom network

[TheDemonLord]

probably Phone A is sending an MMS message as the default format which Phone B can't recognise - check what the default message format on phone A is - it may be set to something other than bog standard SMS