Can't subscribe to internet calendar

I publish my work calendar from our Office365 server so I can view it on my other devices. The published calendar has the format "https://outlook.office365.com/owa/calendar/<some_private_token>/calendar.ics" or "https://outlook.office365.com/owa/calendar/<some_private_token>/calendar.html"

This has been working for several months, and a couple of days it stopped working. I cleared everything and republished the calendar from office365. I know the url is good since:

(1) I can access the .html one on a browser

(2) I subscribed to the .ics from my windows laptop and my windows VM

The problem is now with iCal on my Macbook. What I'm doing is using iCal on Macbook (running Ventura 13.31(a)):

(1) File->New Calendar Subcription->Paste link "https://outlook.office365.com.../calendar.ics"

(2) Click subscribe

(3) After about a minute with a window showing "Subscribing to "https:// ..." there's an error that comes up:

There was an error subscribing to the calendar

Calendar couldn't connect to outlook.office365.com. Make sure you're connected to the internet, and then try again later.

I can assure you I'm connected to the internet -- I'm posting this from the same laptop! and I can access the calendar using the url in a browser

(4) Tried the same with with "https://outlook.office365.com.../calendar.html" (which I'll restate to avoid anyone saying it's a url problem, I can access fine from a browser)

(5) I get an immediate error:

There was an error subscribing to the calendar

The data downloaded from https://outlook.office365.com.../calendar.html isn't valid

So I guess it does want the .ics file, but I get the error above

(6) Went back and tried with http://outlook.office365.com.../calendar.ics (notice I took the s out from http) and after about 15 seconds I get a message that says:

Insecure connection

The connection is not secure. Do you want to continue subscribing

(7) After about 30 seconds of "Processing ..." same error:

There was an error subscribing to the calendar

Calendar couldn't connect to outlook.office365.com. Make sure you're connected to the internet, and then try again later.

Any help from Apple Support?

I'm pretty sure this is an iCal issue (preempting you pointing me to other places) because:

1. I can subscribe to the .ics calendar from two windows computers
2. I can access the url with the .html file on any browser
3. iCal is able to access outlook.office365.com with the .html link (in order to say the data isn't valid), so can it not access it then with the .ics link?

Would appreciate any help. This is very, very frustrating.