Issues with communcation between two Fortinet 600Ds

Hello all

  Last year I installed a Fortinet 600D in replacement of a Cisco 5500 ASA on my local network. Last week, I installed a second 600D at a separate geographical location. After the swap,  I cannot communicate between the two locations utilizing the 600Ds. I can tunnel out of my current location to a separate location still using one of my older Cisco firewalls, then tunnel out of it to the newly installed 600D. However, I cannot even ping between the 600Ds. All settings appear normal.

What is odd is that the unit appears to be issuing a new SSL key every reboot as I have to vim (running RHEL) my known hosts file and delete the previous cert to SSH into it to connect. Any help is appreciated!

OS- RHEL7

Firmware version 6.4.5 Build 1828