When I set Serial monitor window to both NL & CR it does not work, if I set up only newline, it works.
Suppose you set the line ending to CR/NL, and send "1". What is actually sent, then, is "1". When you read everything up to the NL, the string contains "1". When you then compare that to "1", of course they do not match.
When you set the line ending to NL only, , and send "1". What is actually sent, then, is "1". When you read everything up to the NL, the string contains "1". When you then compare that to "1", of course they match.