empty toilet tank

[AngelOSU22]

Hi, I need some help! I woke up this morning with my toilet unable to flush and I see that my tank is mostly empty. It worked just fine last night and I don't believe I turned the water off in my sleep. Everything else water-related in the bathroom works fine. What could be wrong? Thanks for the help everyone!

[DIY Guy]

The fill valve may have failed and that could be the problem. it is easy to replace. however, I would start by turningoff the water at the toilet and disconnecting the fill tube. Put the tube in a bucket and turn it on to check for normal water flow. It tha tchecks out, replace the fill valve.