I have authorized a few developers in the past on my Amazon account without an issue, I currently had my my postage application authorized. Now every time I try to authorize any new developers, I am getting an error from the developer I authorize once I submit my seller ID and their MWS AUTH TOKEN saying that my SELLER ID is invalid and another developer gave me a “Invalid Amazon MWS Credentials” error. I have confirmed access, tried completely re-adding the developer from scratch, I don’t understand why my SELLER ID and MY MWS CREDENTIALS are not being verified by any of the developers anymore. Everything looks good on my end. I have one SELLER ID and my 3 MARKETPLACE IDs and I am using copy & paste for everything when inputting the information. How can my SELLER ID all of a sudden be invalid and how do I fix this? One developer doesn’t ask for a marketplace ID and another does ask for one and I input my main Amazon.com marketplace ID. I need to get this fixed. I am attempting to authorize 3 developers. All of their information was entered correctly and they were confirmed and in my current authorizations list but when I give them my seller ID and the MWS AUTH TOKEN which was generated, I still get errors, from three completely different developers on three different websites. I don’t understand how to fix this. Please help. Thanks in advance.