Wifi sign in adware?
You've been hit by malware - adwares on your case - that redirect you to specific websites. If you check your apps list, you'll notice some unusual apps, with weird names sometimes. Th simplest solution: you'll need to flash your phone, or if you're skilled, uninstall those apps from your phone by rooting your phone and using ADB Shell. Let me know which one you are able to do.