hassan-ibn-abdul-qadir:

Do not panic if the answer to your prayer is delayed

I have noticed that it is a trial when a believer invokes Allaah but his supplication is not answered, even though he may repeat it for a long time!

In such a case, you should understand that this is a test that requires him to be patient, the whispers and suggestive thoughts that come to mind when the supplication of a person is delayed is a kind of sickness that requires treatment.

— Ibn al Jawzi| Captured Thoughts, Pg.189