BX310x(2.7.3) -TCP (TLS Client Mode) Communication is not works perfectly

Hi! I am trying to TCP(TLS) communication between BX3105 & Simple Python TLS Server.
Unfortunately, I couldn’t success this works even using by latest F/W 2.7.3 version.

First of all, I prepared three certifications like below for BX3105 side.

  1. CA CERT(ROOT) 2.Client CERT(Local) 3.Client Key (all certifications are PEM format)

And I upload to three Cert to BX3105 module in according of below step.

  3. Client Key: AT+KPRIVKSTORE=0,1679
    During upload All Certs to BX3105, did not found any error message. (No Error)

And I prepared to server connection with “AT+KTCPCFG=,3,,8443”
(Server IP, Port 8443)
Try to connect with “AT+KTCPCNX=1” command, But Error is occurred.
In sametime Server Error is
“[SSL: PEER_DID_NOT_RETURN_A_CERTIFICATE] peer did not return a certificate”

Also, I captured packet this situation (TLS handshake fail) like below.
Server IP, BX3105 IP

BX3105 does not provide Client(Local) Cert to Server even already valid client certification is uploaded. (Just size is 0)

but When I tried TLS Communication same server and python client as same condition (same CERTs), It’s always succeed.

When TLS Handshake fail is occurred, I don’t know why happened this situation.

Who anybody succeed to TCP-TLS communication similar my case.
Please someone help me.