R Studio Mac axis not showing label

I have a macbook pro 10.14.2 and I'm trying to graph something in R studios for my class. When I run hist() it comes up with 50 warnings (no font could be found for family "Arial") -- the correct graph comes up but the axes have no labels to them. Does anyone know how to fix this?

We don't really have enough info to help you out. Could you ask this with a minimal REPRoducible EXample (reprex)? A reprex makes it much easier for others to understand your issue and figure out how to help.