Are you using SoapySDR in your C program? I’m using it and sometimes I get the cannot deliver frequency, even if I’m always tuned to the same frequency. I currently don’t know how to fix that, as usually once it appears, all subsequent tries give me the same error. What I would do is run Lime Suite then simply do a GUI --> Chip and things would then work again.
There’s been other reports of such error, eg LimeSDR usb Problem
Any ideas @andrewback or @joshblum? Do you think it’s a problem in the Lime or could it be from Soapy?