Orbi Router Able to access cPanel for 1 of my website, but not the other

Hello! 

I have a couple of websites being hosted through inmotionhosting.com and have WordPress installed on them. On one website I can access the cPanel just fine through the backend. The other website I recently (last Monday or Tuesday) changed the primary domain on and since then, the cPanel does not work unless I type it in directly; I can no longer use the backend link.  I have spent a few hours attempting to resolve this with inmotion's tech support.  They say it is a local issue.  The 2083 port is not blocked by my ISP, and it works just fine for one URL, but not the other.

The backend link works if I am on another network (a separate wifi or my phone). It even works, at times, if I reset my Orbi router, but then it eventually stops working.  I receive the error that the server is taking too long to respond.  I do not have any firewalls currently enabled. I have not set up anything beyond the basics on the router.  This does appear to be a local network issue, but for the life of me, I cannot figure out what's going on.

• I receive this error whether I am using Google Chrome, Microsoft Edge, Safari.
• I receive the error on both my PC (just did a fresh restore on it, have not installed any firewall/BitDefender) running Windows 10 and on my Macbook Pro.
• I receive the error on both my Samsung Galaxy S9+ and iPhone 6s, both will load the link if on their 4G plan, but not if going through my home wifi network.
• I can login to cpanel if I go to mydomain.com/cpanel

Router: RBR50 Orbi AC3000

Router Firmware Version: V2.3.1.60

Here is a link that should be working to even pull up the cPanel login page: https://secure256.inmotionhosting.com:2083/login/

Here is a screenshot of what I receive: https://prnt.sc/o2xagf

I've only had the router since March 10th, just outside of the 90 days for me to contact Netgear's tech support.

Any thoughts would be appreciated.