Cant Use Mouse side buttons

i woke up and got on minecraft then it said my setting got reset so i put them back but i noticed that i couldn't use.my side buttons to switch to my 8th and 9th slot in my inventory its been a few days and i got on another account that had it as the 8th and 9th Slot And It worked but i couldn't put the bind as something else but i could still use the bind please help i need the binds