The following are common problems and solutions to fix them.
Cloudflare and caching
Do you use Cloudflare or cache your website?
WordPress REST API
Redirection uses the WordPress REST API, and your site may have disabled this.
Security plugins
Wordfence or other security plugins can block WordPress requests.
WordPress plugins
Sometimes other plugins can interfere with Redirection
A URL is not redirecting
There are many reasons why a URL may not redirect.
A URL is redirecting and I don’t want it to
There are many reasons why a URL may still redirect.
PHP version
What version of PHP does Redirection support?
Redirects or 404s are not being logged
What to do when redirects or 404s are not logged.
Data is not saved
What to do when data is not saved, or an upgrade repeatedly fails with a loop.