Web Query suddenly not working

I am using Excel 2016 and I have a web query that pulls data from a web-based project management system. Literally up until yesterday, it was working great.

The way the web query is set up is that I paste the URL of a report that is generated in our system into the Edit Web Query popup and that directs me, initially, to the splash login page for our system. I log in, and then it takes me to the report. I then click the box next to the table I am importing. Click import, and done. Works great. Our system does have a 30 minute timeout, so I have the query refreshing every 5 minutes so that I have realtime data and it doesn't time out.

For some reason, yesterday suddenly I started receiving the "Query returned to data" error. I check the web query and now it doesn't seem to keep me logged in to our web-based system. I bring up the Edit Web Query popup and every time, it only goes to the splash page. I log in, select the table, click import. Instant error. It's as if it isn't saving the cookie, or something. There is no permanence to my login anymore.

I don't believe I changed anything. Has there been some sort of security policy update? Am I out of luck? Please help! This spreadsheet is my life!

I saved the workbook as Macro Enabled. That worked, then it didn't, then it suddenly started working again. I think it's me. I'm cursed.