It Shows me a Warning inside Blocks, What to do

Inside blocks, I am seeing 1 Warning, and when i click on it it shows me below image


Please Help me out if anyone can guess what is the warning

A tag should be a string not a number i guess.

No Sir, I tried doing so still no results, anymore suggestions please.

What is the exact error?

Sorry, It was my silly mistake i figured it out later, by the way thanks for taking your time for me!

Tell what it was so others can learn. That is the purpose of a forum like this.

Actually I had duplicated the maths block containing no.7 and and forgot to delete it. Further I came across the error and resolved it

Mark it as solution :sunglasses::sunglasses: