What happened was that the European Union passed a law that, among other things, required encryption for login requests on every site. So the Nexus updated their servers, and therefore changed the way the site "talks" to NMM/MO. As HeyYou said, NMM was updated, and the MO2 team released an update for MO1.
Here's how to update MO. It was written for a computer-illiterate person, so apologies for the hand-holding:
I don't know your skill level, so apologies if this is too much info.
The Mod Organizer developers have released a patch that makes this unnecessary. Click here: https://www.nexusmod.../6194?tab=files and scroll down a little until you see "Miscellaneous files", and under it "Mod Organizer 1 Legacy" and a light blue check mark next to it. Click the words "Mod Organizer 1 Legacy", and the box will expand. Then click "Manual Download" and wait for your web browser to download it. Open the file called "Mod Organizer 1 Legacy-6194-1-3-15.zip" and you should see a list of files. Press (on your keyboard) CTRL and A at the same time, and it will select all of them. Then press (again on your keyboard) CTRL and C to copy them. Then go to where you have installed Mod Organizer (most likely C:\Program Files (x86)\Mod Organizer or C:\Games\Mod Organizer ) and press CTRL and P to paste them. Say "yes" or "overwrite" if it asks you. Then you're done!
Edited by TheGreatFalro, 09 November 2018 - 10:17 PM.