Two things: If you recently replaced an old toilet and had to shut off the water supply at the base of the toilet, it is possible that the valve is bad. If it's not a 1/4 turn valve, ex. it's the one you turn more than two or three turns to close, it's possible it worked when you closed it and broke when you reopened it, leaving it only partially open. These are notorious for breaking. Otherwise, I would be incline to replace the supply hose (if you haven't already) and, if it still was not working, replace the fill valve.
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Two things:
If you recently replaced an old toilet and had to shut off the water supply at the base of the toilet, it is possible that the valve is bad. If it's not a 1/4 turn valve, ex. it's the one you turn more than two or three turns to close, it's possible it worked when you closed it and broke when you reopened it, leaving it only partially open. These are notorious for breaking.
Otherwise, I would be incline to replace the supply hose (if you haven't already) and, if it still was not working, replace the fill valve.