Cannot record on added tracks. Error code -9997

I’m recording using an AKG C214 mic connected to a dbx 286s preamp/processor connected to a behringer U-Phoria UM2 audio input device for voice over work on my Windows 10 PC.

I’ve been using Audacity trouble-free for a couple of months. I could add a track, or add as many tracks as I want, and I could record on every track.

Now, suddenly, I can only record on one track. If I add a second track and try to record on it, when I click on the Record button in Audacity, an error message pops up: “Error opening recording device. Error code: -9997 Invalid sample rate.” If I delete the second track, I can go back to the first track and record on it. I cannot record on the first or the second track once the second track has been added. I can only record if there is only one track.

Since everything has been working fine, the first question that I asked myself is, “What changed that could have caused this?” but I can’t think of anything that I did.

I’m using mono tracks set to 44,100 Hz, 32-bit float. The second track that I add has the same sample rate as the first track, as set in preferences.

I have tried rebooting, reinstalling Audacity, and reinstalling the driver for the UM2, but I get the same result.

When I track down the Audacity error code I read this:
“-9997 Invalid sample rate: make sure that you have matched the sample rate in Audacity with that set on your device - both for playback and recording.”

I’m not sure what that means since there is nowhere on the physical device to set the sample rate, but if I go into Windows and look at the device properties for the Behringer UM2, I see that it is configured as a “2 channel, 16 bit, 44100 Hz (CD Quality)” device. The only other option is 16-bit DVD quality at 48000 Hz, but that would not be right. The device description correctly matches the Audacity sample rate of 44,100, so I don’t understand why it is throwing this particular error.

Has anyone seen this before, or knows what I need to do to correct it so that I can record on multiple tracks? It’s probably something simple, but I just can’t seem to find it.

Nevermind. I found that both MME and Windows Directsound hosts allow multiple tracks (although I was sure that I tried them before with no luck).

Still, these hosts record at a lower gain than the WASAPI host, but that is adjustable so I will press on. Sorry to have bothered you all.