I can connect to my router with wifi, but I can't ping the router or anything else

I recently installed Mint 19.k3. I had no network connection. A friend set up the Ethernet interface, and my lan network works fine. I'm trying to get wireless working. I purchased a dual mode USB adapter, and installed the driver per the instructions that came with it. I couldn't access the internet or even ping the router with wifi. The support for the adapter looked at the syslog file and said that the driver is installed correctly and is able to connect to the access point. He says I must have a configuration problem.

Bottom line, I can connect to a router's SSID, but can't ping the router. I have no idea what to do next! How do I troubleshoot this problem?