Could not authorize build request

I have an open source project on github that I’m using travis-ci to test. I made commit to this repo earlier today and travis-ci didn’t run the test. The commit shows up in Travis CI - Test and Deploy with Confidence but it’s showing up with a “Could not authorize build request” error. I tried to create a custom build but that gets me the same error.

I don’t understand. I thought Travis CI was free for open source projects?

Turns out I wasn’t subscribed to any plan. I selected the Free plan from this link and was able to rerun the builds without issue.