HI Abhijeet, welcome to the SonarSource Community!
The error in this case is pretty clear: it looks like the key you saved as part of your github configuration is invalid. You want to make sure the entire key value is pasted including the text -----BEGIN RSA PRIVATE KEY----- through and including the text -----END RSA PRIVATE KEY-----
FYI, it’s considered rude to call out a specific person to help you unless you’ve already been discussing a situation with them. There are any number of SonarSourcers and other Community members who can help you out.
I Apologies for tagging you personally, because of my strict deadline I have did it this way and I have been trying ALM configuration from many days and not able to understand how private key work irrespective of using private key in ALM conf. and nowhere mentioned in doc that I have to copy paste as per your reply so I got confused.