What Type of Connector is This?

My WiFi has started to be absolutely terrible and I'm investing in Ethernet. I know my house has Ethernet in the walls, but it hasn't been used ever and my house is 10+ years old. I bought some Cat5e cables but they didn't fit in the ports in the wall. None of the other Ethernet cables I have in my house fit into these ports either, but I've looked at all the wiring that my router is plugged into and these jacks aren't wired for telephones. I need someone to help identify this port. 

Here's a picture of the port:  

If you can, remove the jack from the wall and see if there is a model number on it you can search up. You are  probable going to have to replace these jacks with rj45 ones and do some rewiring.

It looks like someone shoved hot glue into an RJ-11 plate.

I believe some of those jacks come with a clear gel that covers the pins to protect them from corrosion.  That is probably what looks like hot glue.

What I find very strange is that the wires that you can see behind the jacks are all gray, you really should take apart that outlet and find out what kind of connections are there, could be for something else and not Ethernet.