The problem with call transfer

Distro (FreePBX, Asterisk Ver.

The problem is the following:

The city receives a call to any extension number, for example 101.
With internal number 101 transfer the call to 102, dialing ##102.
Everything is fine. But then there is a problem.
If the extension 102 also wants to transfer the call (for example 103), after dialing ## play the voice command “transfer”.
And then after dialing 103 or any extension number the connection is dropped.

How to solve the problem with the call transfer?

You are using unsupported versions of FreePBX and Asterisk, so i am unable to test with your setup, but using Asterisk/FreePBX 13/13 I can make as many blind transfers as I want.

If you post the sanitized Asterisk log lines from a failed transfer, there may be a clue there to what the issue is.