My tank will not fill after flushing ( not the bowl) however when I run water into the sink it fills

my tank will not fill after flushing ( not the bowl) however when I run water into the sink it fills

This is a common complaint in my area. Easy fix! There's a washer with a hole that swells shut cutting off the flow.
Now for the slow fill: Sometimes the orifice in the seal will swell shut and slow the volume of water entering your tank. This is a common problem with these ballcocks. They have a small washer with a hole,(see image) in the center that swells shut in time preventing water from entering the tank.
Purchase a FluidMaster Seal#242 from your local big box store. To replace it you will have to shut the water off to the tank and take the tank lid off. Twist the top of the ballcock off counterclockwise, (see image in above post, ) and pull up. Pry out the seal and replace it. Reassemble, turn the water back on and give it a flush. Better now? Regards and thanks for rating my answer, Tom