SharePoint 2010 Set-SPManagedAccount Error

Hi, hoping someone may have encountered this error before. I've been updating the Managed Accounts for a client environment for the past year, but when I attempted to update them yesterday I received the following error:

    "The system detected a possible attempt to compromise security. Please ensure that you can contact the server that authenticated you."

I have updated these accounts using the Set-SPManagedAccount cmdlet 3 or 4 times over the past year and never received this error. I was given a new account to use due to a coworker leaving my company, and I don't believe I missed any permissions when updating them to match the previous account.

I'm currently at a loss as to what the cause of this could be since there haven't been any changes to the server, and the only difference that I know of is the account.

Thanks in advance for any help.

    - James V