The use of symbols in The Sims: FreePlay is so widespread, and the symbols being used seem to be so obvious that it is a wonder that anyone could be confused by them, and yet just such circumstance appears to be so!
One issue that tends to exacerbate the matter is the fact that the Sim who you are attempting to perform an action for can sometimes be off-screen so you cannot see the resulting picto-notice and so all that you have to go by is hearing the negative sound notice but, as you did nto see the picto-notice, you don't know WHY there is a negative notice!
Among the number of picto-notices that can appear in the game, the two most common are the following:
BLUE FOOTPRINT BUBBLE: This is the Symbol to indicate no route or access is present.
Nine times out of ten when you get this symbol it means that the object you are trying to access or use is facing in the wrong direction - that is to say the object (let's say it is a record player) has been placed so that the controls are actually facing the wall (an easy mistake to make with some devices) so your Sim has no access to the controls.
The Horse-focused collections are one of the greatest shaped planned impediments to forward progress so far encountered! But then again the prize for getting through that is a Unicorn, and how cool is that?!
The 10th time out of 10 what has happened is another object is blocking access to the device or object, even though it does not appear
to be doing so. The simple fix for this situation is to adjust the location of the object or move the objects around it.
RED CIRCLE AND LINE: This is the International Symbol for Negative and NO.
When a red circle and diagonal line through it appear on a sign you know that this means you cannot do whatever the sign is. So for example when you see the Blue "P" symbol, which is the international symbol for Parking - and it has a red-circle-and-line that clearly means that there is No Parking in that spot.
In the case of The Sims: FreePlay this symbol, when it pops up in a thought-balloon over your Sim head, it means that your Sim cannot complete the action that you just attempted.
So for example if you tried to have your Sim move to a specific location and you get that symbol and the negative sound effect, it means that the Sim has not route to that location, so you need to check the route.