Microsoft is aware of issues some Windows 10 users have been experiencing when trying to sign into the Windows Store. The good news is that those problems will hopefully be solved soon via an upcoming patch for the operating system.
Windows Central contacted Microsoft to ask about the Windows 10 store problems reports and received this brief response from a company spokesperson
"This issue will be resolved within the next 48 hours via Windows Update."
Microsoft's statement didn't offer a reason for what might be causing these problems. Some have speculated that the issues were the result of the recent culmative update for Windows 10 that was released last week but there's been no real evidence to back that up.