oreocookies

For at least the past year, maybe two, whenever I have tried to change my flights on the Southwest website, I can't. It always gives me an error message that is just a random string of numbers and letters:

I can click "re-select" and do it until I'm blue in the face, and it will always give me this error. It doesn't matter which browser I use. It gives me the same error in my phone app. I can try over and over and it always happens. It's incredibly annoying. Usually I resort to canceling my original flight and then re-booking a new one, but I would much rather just change it so there's less risk involved. My mom is able to change flights on Southwest without any problems at all.

Any idea what the issue could be? Anyone have this issue and get it resolved?