The Moon is a card of intuition and psychic forces, so let go of your conscious mental blocks or negative self-talk, and allow your intuition to guide you

Astronotus ocellatus

The Moon is a card of illusion and deception, and therefore often suggests a time when something is not as it appears to be. 

Vigilance and clear perception will be necessary to find that which is hidden before it is too late. 

 
If other cards in the reading are negative, then the Moon shows that not all is as wonderful as you would think and there are still hidden forces at play that may unravel your success.

You may be idealising the situation, and ignoring the fact that potential for failure exists among success. 

If the other cards are generally positive, then the Moon suggests that you are letting your imagination run away with you, and that things are not nearly as bad as they seem. 

 
In both cases you must open your eyes and see what it really going on. 

Guard against accepting illusions as they may cause an error in your judgement.

https://www.biddytarot.com/tarot-card-meanings/major-arcana/moon/