I am only replaying so I can be of a help to you guys! used 2 different browsers: MX5 / Mircrosoft Edge
Of course I use the normal mode with my GMAIL account! No incognito!
However, I have been looking and found that your URL link has an invalid ssl certificate.
I would like to add, if this is an online game, I would kindly refuse to playtest online games, because I always face problems with that and it takes a lot of days and energy to find what issues are making the game not run! (Suggestion: it is better to add a downloadable files, browser games tend to have issues a lot).
Best of luck Saqirmdevx!