I’m using standard Safari on iPhone, iPad, MacBook without any VPN so a Thai 3BB assigned IP. I could access the UM page on Facebook without any problems but clicking the link on the home page returned the error. Like I said, cleared cookies & website data & logged in again but it didn’t make any difference.
Just returned to a device, saw your reply so thought I’d try again & this time no problems
Maybe trying again & again with your admin login reset something, who knows?
Seems okay now, you just need to get some up to date posts