AES encryption used by the server (C-sharp), CBC,Pkcs7.

the key vector on the server side is defined as follows:

public byte[] _iv = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF, 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };

crypto-js used in the front end
but the encryption results are always inconsistent
I don"t know how to match the iv on the server
ask the boss for advice.

original text: "1234"
key: "1234123412341234"
ciphertext: "bH0SH7ITQA8FUEMtX3P5yg=="