Shower door was pushed off track. Can it be fixed? Is it a simple solution

If it's a standard slider...you may be able to just lift the panel to get the wheels on track. Do this gingerly if the panel is frameless.

Thanks for the appointment on 9/24/21. Lower tracks a problem. They both measure 21 1/2" in width. The inside door will not track and swings "out in the breeze". The outside door tracks "pretty good". The glass doors (2) are in good condition. They measure 67" in height and 23 1/2" in width. The door frame is solid, including the base and base tracking being solid. Age of shower stall and installation is about 12 years old. My main concern is saftey for user so that doors do not release and fall off when showering. I would appreciate your reply to this note. I will be patient an await your service call. Please consider bringing new lower tracking aluminum and also the upper roller are loose.