Ive switched to Firefox for my browning on desktop and phone. But I am still unable to use it for web development, local host won't store third party cookies.

Ive switched to Firefox for my browning on desktop and phone. But I am still unable to use it for web development, local host won't store third party cookies. I've tried switching off different settings with no luck. Does anyone know if anything can be done? I am trying to use Firefox developer edition