Why can I airdrop from my MacBook to my iPhone, but not my iPhone to my Macbook?

Using a MacBook Pro on Catalina and an iPhone 7. Up until recently, I've never had an issue with airdrop before, but now they won't go through in one direction.

• On my MacBook, I go to share with airdrop, my phone shows up, I click on it, and the file gets sent. No problem.
• On my phone, I say share with airdrop, my MacBook shows up, I click on it, and...nothing. Just sits on "waiting."

They're both using the same network and have bluetooth on. There doesn't seem to be anything fundamentally blocking the transfer or preventing one device from detecting the other, since it works one direction and each device shows up as an airdrop option on the other.

What could be causing my computer to not detect it's being sent something (or my phone to think its sending something without actually doing so)?

I think this could be a problem of the Handoff feature. Deactivate Handoff both on your Mac and your iPhone. Wait for a couple of minutes and then turn Handoff on again on both devices and take care that both devices are unlocked at the same time!