Here are a few ways to rewrite “The request could not be satisfied,” with varying levels of formality and emphasis:

More Direct/Formal:

• The request failed.
• The request was unsuccessful.
• The request could not be fulfilled.
• We were unable to process your request.
• Your request could not be completed.
• The request encountered an error.

Less Formal/More User-Friendly:

• We couldn’t complete your request.
• There was a problem processing your request.
• Something went wrong with your request.
• We ran into a problem fulfilling your request.

Emphasizing the reason (if known):

• The request could not be satisfied due to [reason]. (e.g., …due to insufficient funds.)
• We were unable to satisfy the request because [reason].

More Specific (depending on context):

• The resource you requested is unavailable.
• The server is currently unable to handle the request.
• There was an error in your request.
• Access to the requested information is denied.

The best choice depends on the context in which the title will be used and the audience you’re trying to reach.