OpenVPN - can connect but can't ping or access the server

I too had the same issue last week. It got fixed when I changed the line in the OpenVPN server configuration file from

push "redirect-gateway def1"

to

push "redirect-gateway def"

Seems you have answered your own question:

The client is connected and has an IP in the VPN range.

Normally, the VPN clients has it's own IP range, as in your configuration (10.8.x.x). You should set up the routing on the server, so, for example, the 10.8.0.1 will be masqueraded to 10.10.0.100 or whatever your local intranet range is...