Your landlord can request verification of your ESA's legitimacy under the Fair Housing Act if your disability or need isn't obvious. Provide a valid ESA letter from a licensed mental health professional confirming your disability-related need. They may check the provider's credentials or contact them (with your permission) to confirm authenticity. They cannot demand extra forms, certifications, or details about your diagnosis. Denials must be based on valid reasons (e.g., direct threat or undue burden), not skepticism alone. If challenged, you can file a complaint with HUD for potential FHA violation.