A business can refuse to accept a power of attorney if it has a valid reason for doing so. A person or business is not required to do business with your agent if they would not be required to do business with you. They also are not required to honor your agent’s authority if your agent previously breached any agreement with them. If your agent asks a bank or financial institution to open a deposit account or take out a loan for you, it can refuse if you do not already have an account with it.
A person dealing with your agent can ask for information to prove the validity of the power of attorney. If they refuse to honor your agent’s authority without a valid reason, your agent can ask a court to compel them to honor the agent’s authority.