@michaela Debugging your build process is outside of Netlify’s ‘Scope of Support’:
https://www.netlify.com/support-scope/
Base functionality of Netlify’s build and deploy pipeline is supported, but we cannot help you debug any source code used either during build or after deployment.
Since you mention that your site is connected to WordPress and the error started occurring after you changed content, it’s likely that changed content has caused the issue.
This thread is unrelated to your precise issue, (as they’re running different code), but serves as a good recent example where someone else found that ‘content can cause an error’:
https://answers.netlify.com/t/sudden-build-failure/139631/2