Comment by JSoet

I had a similar story from just a few weeks ago. One of my colleagues was having trouble logging into his test instance, but he was the only one having this problem. Tried on my machine and it worked fine, made sure we were both using the exact same version of the code, etc. and he continued to have the problem while I didn't... Eventually we realized that he only had this problem on firefox and not chrome, and then we finally realized that the problem was in Firefox he had his credentials saved and was hitting the 'Login' button, whereas on Chrome he was typing them in and hitting enter, which is apparently what I and the rest of my colleagues also do, but luckily he found that bug with a slight difference in the logic between the two paths before it went to production.