Desktop
You may check if your Chat settings are Activated. To do so, you must go to your “Settings > More Settings > Chat” and tick the options “Show Player Chat” and “Draw Player Chat Ballons”.
Mobile
You should click on the 3 strokes in the upper left corner, then settings and then in the Chat section select "Show Player Chat" and "Show Players Chat Balloons" as you can see in the image below.
