This could be for a number of reasons.

• Make sure you are selecting the correct account type when linking to your account. For example you will need to select Chase – Bank account if it's your checking or savings account and Chase – Credit Card if you're linking your credit card
• Try logging into the destination site and confirm your credentials are correct 
• Make sure the destination site is not down for maintenance at the time you are trying to link the account 
• Confirm that there is no splash page upon logging in that you must acknowledge prior to accessing the account (i.e. New Terms & Conditions). Navigate through the destination site in its entirety, as sometimes the error could occur in other places on their website.
• Confirm your security questions and answers making sure to take note of spelling and case-sensitivity 
• Consider the time in which you are attempting to link the accounts. Errors can occur when the destination site or our site is undergoing a refresh (We go through a nightly refresh between 12am-3am EST) 

If all else fails, please contact support with the following:

• The Error Message you are receiving 
• The Date and Time in which you were attempting to link your account 
• The name of the institution or service provider holding that account (ie. Chase or Comcast) 
• The URL you normally go through to log in to that account