Receiver SFTP Error : No private key with signing capability found in &&&&

Hello SFTP/PGP Experts,

Problem Statement: It is a SOAP to SFTP (with PGP encryption) Scenario, where PI needs to sign and encrypt the document and to be send to SFTP server.

Steps followed for configuration:

step 1) Followed the the document : Generating SSH Keys for SFTP Adapters - Type 2 - Process Integration - SCN Wiki for creation and configuration of keys.

Step 2) Copied the receiver's SFTP public key in .ssh folder in PI system and forwarded my public key to SFTP server team.

Step 3) Repeated step 1 to create another private key to be used for signing and created a new entry in the same view but selected the option of "Select key Pair" for signing and mentioned the previously created private key.

When I trigger the message, it fails in receiver adapter with error :: "No private key with signing capability found in '/home/x03adm/.ssh/emsapx03_rsa.key "

I tried by selecting both the private keys (I created as mentioned in above steps) in PGP configuration in Receiver SFTP Adapter.

Please see the adapter config screenshot below:

Expecting help soon!!

Thanks