My iphone 5s saying sim not valid

[Navjot Ghuman]

I checked by icloud it says activation off this device can b used by a new user

 

[Highrisedrifter]

Is the phone locked to a carrier? Also, if it isn't, or if it is but you are using a SIM from the correct carrier, remove and gently clean the sim with a lint-free cloth and then re-seat it back in the tray and re-insert it back into the phone. This sometimes helps.