Confirm page/Paypal Advanced problem

I had a big problem with Paypal over a year ago with this client's website (prostuffcleaner.com) and Ray did an excellent job in finally rooting out the solution. My client called yesterday and said he had not received orders in a long time so I did a test on the system and received the error that is detailed in the screenshot. Any ideas now what I'm dealing with? The credentials in the confirm page match those in the Paypal manager.
Thanks,
David Hampton

I tried logging in at: http://manager.paypal.com

Using the credentials listed in the screen capture, and I couldn't log in. I think the vendor, username, or password must be wrong.

Sorry, I had to change the password because Paypal required it. The credentials are:
Paypal

You just have to update them in your php page as well and it should start working. (by the way they shouldn't have been posted in the public part of your post, you might want to change them again before updating the php pages, since they could have been viewed by anyone that came to our forum)

Once you update them and try again if you still get errors, send me the error response like you did before in the private area and I can try to determine what went wrong.

Hi Ray please see the private message,
thanks,

I still can't log in to https://manager.paypal.com/login.do with the new credentials.

Please see private message...

The only difference was the lower case 'P' in PayPal. Try updating that on your php page and see if that makes a difference. It did for me when trying to log in.

See private message

Let's try updating the password to not include a # sign. It appears to be properly encoded, but that could be the issue. Maybe try just a combination of letters and numbers for now to eliminate that as the potential cause. Hash signs do need to be encoded because they are used for anchor links, so that shouldn't be an issue, but better to eliminate that since we are getting an authentication error.