IPsec site to site tunnel between TMG and Cisco fails- another scenario

Issue/Scenario: Recently  I worked on a Ipsec site to site Scenario between TMG and Cisco. Tunnel between these two end point was not getting established. Troubleshooting approach 1. Checked the settings of the site to site IPsec tunnel. 2. In the addresses tab of the tunnel properties on the TMG server remote end point Ip address…