Hello @KarenT51 ,
I checked out your segments and pre-built segments with different numbers of contacts showing per page, and I was able to get all pages to load for me. It's possible you're experiencing some kind of connectivity error, such as extension interference or a caching error. Is this error occurring in other browsers, or when in Incognito / Private browsing? Are you running any VPNs or other security software that may need to have our domains safelisted?
Does showing more contacts per page (e.g. 100, 250, or 500) allow you to see all your contacts / allow you to access all pages?