I just wanted to +1 on this. I found this thread because I was experiencing this same issue with ACF Pro 5.5.7. Everything worked fine on my MediaTemple VPS and in my entire teams’ local development environment. When the site was moved to the client’s host of choice (not GoDaddy), the options page wouldn’t update and would redirect to a 404. I removed the https:// from the link fields and hard-coded it into the PHP file and everything worked fine.
