Good question, Ren - that setting is supposed to persist after saving, so if it’s reverting back after you reload the page or reboot the router, it’s likely a small firmware bug. You can try these quick checks: Make sure you’re running the latest firmware version (sometimes a newer build quietly fixes small UI issues like this). After toggling “Increase Contrast”, click Save, then clear your browser cache or try another browser to see if it’s a visual caching issue. If it still doesn’t stay enabled after reboot, it’s most likely a firmware UI bug - you can report it directly through the TP-Link Feedback option on the router’s web interface or the Tether app. Hopefully this gets fixed in an upcoming firmware update. Let us know which firmware version you’re on, so we can check if it’s been reported for that build

Hello @516616666109887 ,

Thanks for contacting our community.

For comparison, have you tried a different browser? Or, have you tried to log in to the router via another clients? Like a different PC, or mobile phone.