How to set up unconditional mail forwarding from Google Apps to an internal mail server?

Question

gmail

Good afternoon!
The situation is as follows: there is a Groupwise mail server that all employees use. There is a GAFE account with our domain linked to it.
The task is this: you need to configure google apps in such a way that all mail received by it is automatically sent to the appropriate recipients on the Groupwise server.
What was done:

• added MX records for the domain pointing to google servers
  
• waited for the DNS update to disperse
  
• configured routing in GAFE indicating the external IP address of our Groupwise
  

As a result, when I try to send a letter to my internal address, I get a rejection from Google:
Delivery to the following recipient failed permanently:
[email protected]
Technical details of permanent failure:
A policy required TLS transmission, but a TLS connection could not be established. Learn more: https://support.google.com/a/answer/2520500
What does TLS have to do with it?! Where to dig, any ideas?
I understand that there is little information, I didn’t give any details, however, can anyone come across redirection from Google to another mail server?