@l8dyaj
I'm glad to hear that call transfers are working well for you. Since others are experiencing issues with the calls hanging up, let's try to troubleshoot the problem. It's good to know that you've already checked for spam flags and that both parties are using the same service provider.
To assist you further, I'll need to check the logs associated with the call IDs you've provided. This will help us understand if there are any error messages or issues with the system handling SIP REFER messages, which are used for call transfers.
Please hold on for a moment while I look into this for you.