Well what messenger are you using? If it isn't working with stock, then try a 3rd party alternative. This is not uncommon with CM for CDMA devices as typically CM is built for GSM and then adapted to work with CDMA. Sometimes there's little weird things like that. Did you check in the thread for the rom you are using to see if other users are reporting similar problems? It's also possible the APNs are different from GB to KK. That happens often.
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