Hi Mani,
Users connecting to which tunnel group are facing the issue with mail access.
The basic point here is that we nede to have routes to the VPN pool on all the layer 3 devices between the VPN server (ASA) and the Mail server,
pointing traffic to the VPN Client to the ASA.
For ex,
Server ---R3---R2----R1---ASA VPN pool is Y.
1. We need the default gateway on the Serer to be R3.
2. We need a route on R3 pointing traffic to the VPN pool (Y) to R2.
3. We need a route on R2 pointing traffic to the VPN pool (Y) to R1.
4. We need a route on R1 pointing traffic to the VPN pool (Y) to ASA.
Hope this helps.
Cheers,
Nash.