Users on IE and Edge have to log in twice on Magento 2 store

Question

I was tasked on fixing JS console errors and browser testing for a Magento site that someone else developed (I assume the original developers quit). I got this finished, but now I am encountering a strange issue on login.

On Edge, IE11, and Chrome Incognito (not normal Chrome) this is what happens:

1. User clicks login link and goes to login page
2. User fills in information and submits form.
3. Page redirects (302) back to the login page and there is NO error message, console error, etc.
4. User fills out login information again, and this time (without fail) the login works.

It's very frustrating. I've tried the following:

1. Clearing cache
2. Checking cookies before and after. This is difficult, because I cannot replicate the issue with any regularity on normal chrome, which is where I can view the cookies. Clearing cache and cookies still does not replicate the issue consistently.

Answer 1

I seem to have fixed this myself after a couple hours of tinkering. The fix was going to Store configuration > General > Web, and then opening up "Default Cookie Settings".

Here, I changed the cookie domain from .example.com to www.example.com since www is forced on the domain and everything works as expected on all browsers. This may not be the case if the domain was non-www.