When Defender location Blacklisting is enabled for just the UK (and no doubt other countries outside the US as well), the My Hub services such as Automate, Uptime, etc.etc. fail as the IP addresses of the WPMU Dev services is (I guess) in the US.
As a workaround, I have so far managed to guess the following IPs, rightly or wrongly, using the server access log files.
Shouldn't the Defender plugin should already know which IPs are required to be allowed through as a hard-coded whitelist of relevant IPs or something rather than expecting the user to know them and input them manually? Additionally, users wouldn't know if the IP addresses ever change and when dealing with multiple sites, as I do, it's an administrative nightmare to keep them updated.