The first thing to check is whether your router decided to issue a different IP address to that device this time.
Even if the IP address has not changed, sometimes you have to close the browser tab, open a new one and type in the IP address manually.
The advice that usually goes along with that is to clear the cache on your browser too. But I just happened to have to do that yesterday, and it was no fun having to get all my sites back to the way I wanted them afterward. So do what you can before resorting to clearing the cache.