PHP session and header warnings break site health
PHP session and header warnings appear in the debug log and, after an update, break REST API calls on the site.
Tier II · Emerging Problems that are still building up.
3 public reports · first reported 7 October 2023 · last reported 3 October 2026
What's going wrong
After certain plugin updates, site owners see PHP warnings about sessions or headers already sent, and in one case Site Health reported critical errors that blocked the REST API and the block editor.
AI-assisted: written with the help of AI from the reports. The idea report has the full summary.
In the idea report
- The full summary.
- The products the 3 reports are about, and how many came each month.
- Related problems.
No business has been found with this problem yet, so the report has no contacts. All sales are final — no refunds. Pricing.