A bit surprise to see the discussion still going on. Thank you Husna QA to keep posting on behalf of me when I was not active in the forum.
@LoyceV, I am not clear if you were able to solve your problem yet,
this did not give me a clear idea of your struggling.
But wait, if I certify for everyone instead of just myself, it works!
Did you have your own PGP private key imported? I hope you did not import your public key instead of thinking that you are importing your private key.
It's not that hard. Let's start over.
1. You will need to have your private key imported first of all.

Do you see yours in
bold? If not
bold then you have imported your public key and this is the reason it's not working.
2. You will need to import the public key of the message senders, this will ask your password so have it with you.

3. Copy the message and from the try verify it.

Only three times you are interacting with the software. This is not too hard

This is the error I get
This is where it was discussed. Credit to Husna QA. I also just noticed that the server in my initial post is down.