Too many Invalid Shares

Hello Miners,
i did a lot of things and i did read a lot of post here that they have same exactly problems with me ,
i have a lot of invalid shares , i did lower OC still the same thing , i did also downgrade still the same thing , i don’t know since when started with me having issues with invalid Shares its become more invalid shares , i got tired of restarting and rebooting whatever is , i just what to know the invalid share from where is coming ? is that power issues or weak network or ??? i change everything to new but still the same thing happen to me