Find the error its impossible 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20?

The errors are grammatical. The email came to me as follows:
"Find the error, its impossible
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20"

Error 1: "Find the error" is a sentence and should end with a period.
Error 2: "its" is possessive but should be a contraction of "it is:" therefore, it should have an apostrophe.
Error 3: "Since "it's impossible" is a sentence, "it's" should have the i capitalized.
Error 4: "Since "It's impossible" is a sentence, it should have punctuation at its end. Suggestions are a period or colon.

At least two more errors as 1) It's not impossible. 2) Since there are at least 3 and if including the two you included then 5, error is not singular but plural and should be "errors."

(The original riddle from Facebook is explained in the related question below.)