You might want to read
https://bitcointalk.org/index.php?topic=826374.0.
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BUT, the public address is f.e. 14DMsSty9S6M51Bxh3X2ZiFhRvdfNhXAjV, why is that? I thought multisig adressess always start with a 3? Is the 3 at the beginning only optional?
Address starting with 1 is pay-to-pubkey-hash (P2PKH) and address starting with 3 is pay-to-script-hash (P2SH). You can't interchange 1 & 3 or any other letter in an address. It will result in an entirely different address than yours or end up with an invalid(unusable) address.
https://bitcointalk.org/index.php?topic=1064545.msg11410590#msg11410590