A hosting firewall or web application firewall may reject a settings request. A common example is ModSecurity. This happens most often when a field contains HTML, JavaScript, an iframe, or ad code.
- Check that you are signed in as an administrator. Write down the exact page, time, and field that causes the error.
- Check the web-server and firewall logs, or ask the hosting provider for the rule ID that blocked that request.
- Ask the provider to whitelist the specific false-positive rule for the required request, then save and test again.
Do not disable the firewall for the whole server just to avoid one rule. Do normal text-only settings also fail? Then check the file permissions and the server error log. Also check if the request reaches AdLinkFly before you decide that the content filter is the cause.