Cant connect to M1 via network cable, getting system did not respond

I am trying to access my M1 Gold via the ElkRP and the network. The device disconnects after verifying identity, and it says "system did not respond" and then invalid information.
I tried via secure and unsecure and it doesnt work. I know the cable should be good, because I currently have to send me an email when the alarm is armed or disarmed, and I get those emails.
 
Any suggestions?
 
Thank you
 

When was the last time that you were able to access the M1 via RP2?  Recently?  Or a long time ago?  Has anything changed in between, such as you are using a new/different PC, or you upgraded the OS from Win7 to Win10?

RAL's probably on the right path... You can't access an M1 from W10, so if you upgraded, you would've lost access.  W10 abandons the weaker encryption that the M1 uses.  In order to make the M1 compatible, you have to upgrade the XEP's firmware to a new version that wipes out the built in webserver, but adds the better encryption required for W10.