Error while reading chars string from s7 200 smart

[Diptee24]

hi sir,
i am reading 6-7 address at a time using below format to read string. but i am getting error : b' ISO : Bad PDU format'. each plc address contains 15 byte.
client.read_area(snap7.types.Areas.DB,1,3200,15).decode()

also if i use snap7.util.get_string(buffer1,3172,15) it gives me an error.
please suggest some solution.
thank you.

[nikteliy]

Could you capture packets using Wireshark and post them here in .pcapng format? This will help figure out what's wrong with the PDU format