my IP address is getting blocked

This problem has been going on now for a few years.   Everything will be working fine then all of a sudden I can no longer

go to a website with my computer or a standalone Raspberry PI hotspot I have that I connect through for certain occasions.

  I have called COX and they claim they are not blocking IP addresses.  I contacted the website that is being blocked and they say the same thing.  The only way I have found to get a new IP address is to switch my router with another exact router and that forces a new IP address.   After a few days I switch back to my previous router and I get a new IP address and all is wokring again.    This has been puzzling me for a few years.   The problem happens maybe once a year.  When I do the router change all works.  Then after a few days I switch back to the original router and all is good no blocking of the website I need to go to.

I have power cycled my router and modem with no luck.  As long as the modem connects to the same router it doesn't fix the problem and also doesn't change the IP addres which for the last few years always chnages the problem.

If on my computer I use a VPN like IPvanish, I don't have the problem however I can't install that on my Raspberry Pi computer.

Any assistance would be appreciated.  The problem just happeend today and I had to switch to my backup router to get a new IP address to solve the problem.  In a few days I will switch back to the originall hoping to get another new IP address, anything other than what the original router has now.  This change in IP address is due to a differenent MAC address in the 2 routers.

Ken