“I cannot think of anyone” is often the refrain to many people’s request for business referrals.

First, is it clear to both parties why that referral source would want to make you their priority now, and trade their “currency”, hopefully, a peer-level trusting relationship, for your benefit?

If that is not immediately apparent, there is no energy to power your referral request. You are turning the ignition (request) but experiencing a flat battery!