Try to show the icon of the app but it displayed an error message

Question:
I changed the secret code to #4779*, and then I made a call with number #1234* to show the icon of the app again, but it displays the error message:

Error performing request. Unknown Error.

I am in Pakistan.

Answer:

In most cases, the customers made a mistake to make a call with *4779# instead of #4779*.
Please start with symbol # and end with *.
It will fix the issue.