What this means? offline address/tx generation

Hi there , My name’s Samutsinth

We have been trying to generate address + privateKey pair compatible with xxxcoin (using secp256r1 instead of `secp256k1`) and using your prefix (PUBKEY_ADDRESS = 50).
Here is the example of the address that we’ve got: MMyevnCKFexH8785tWVveFxyiE9YqMjGMX.
Unfortunately xxxcoin client replies as Invalid xxxCoin address

we are using bitcoinjs-lib to generate addresses (to be precise - this version bitcoinjs-lib-secp256r1 ทางเข้าufabet

Have you ever succeeded with offline address generation and offline transaction generation using any programming language?

Some guy asked like above, then how can I reply?
xxxcoin is based on 0.8 version maxcoin (keccak algorithm), and is now integrating process of some exchange.

Thank you