Error message using Audacity to go from tape deck to laptop

A year ago I hooked my tape deck up to my MacBook Air because I wanted to digitize an old cassette tape. I used Audacity to do so and it worked just fine.

Today I'm trying to do the same thing, but when I click the red "Record" button on Audacity, I get this error message: "Error while opening sound device. Please check the recording device settings and the project sample rate."

I've checked all of the (what I think are) correct boxes in the System Preferences for both the laptop and Audacity. I checked all of the input/output choices on the main Audacity screen and they all seem to be in order.

Since I had no problem using Audacity to record my project last year, I have a feeling that perhaps one setting is off and I can't figure out which it is. My laptop's OS has not changed. Can anyone please fill me in? Thanks.