No, that is not the solution.
The problem is that the content on gitHub from which the site is built, is not reflected in what github.io serves.
There is an unpredicatble delay which can be seconds or hours.
If clearing your cache/removing cookies doesn't work as explained by @yangciou, I would recommend reaching out to private support with the name and link of the repository you are working with. They should be able to take a closer look.
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It happened to me too. What i understand is you need to clear the cache of your browser. I try on other browser it is working fine. Please clear cache and try hope it works....