If an HTTP Error 500 persists for a specific manga source, what advanced troubleshooting can I perform within Tachiyomi?

If the error is persistent for a particular source, try updating the relevant Tachiyomi extension for that source via `Browse > Extensions`. If that doesn't work, clearing the cache for that specific extension (if the option is available within the extension settings) or even Tachiyomi's overall cache (`Settings > General > Clear cache`) can sometimes help. As a last resort, you might consider uninstalling and reinstalling the problematic extension.