The last couple of days, I get the following message trying to access medicare.gov (and medicaid.gov (Reference # varies):
Access Denied
You don't have permission to access "http://www.medicare.gov/" on this server.
Reference #18.aeb8ca41.1537318099.2c1c890
This occurs both via my Windows 10 laptop using Chrome and Firefox (latest versions) and my Pixel XL using Chrome (latest version). I use Norton Security's firewall. As far as know, there have been no major updates on my system.
I have never had any problems accessing these sites. As far as I can determine, these are the only sites I cannot access.