The encryption certificate for this board was not automatically renewed last night as the credit card I had on file with the Certificate Authority had expired.
Since the actual certificate expired at midnight, browsers just refused to connect.
Yes, they did email me last week to let me know but I get over 1200 emails a day, so it just fell through the cracks.
I manually renewed it and updated the board to the latest version of software at the same time. It should be fine now.
Sorry about that