Has WD ever recorded data from the Davis?
Are you using a Serial or USB datalogger?
If you have a USB datalogger, when you set it up, did you use Weatherlink to find the COM port and if/when doing this did you tell Weatherlink that you had a Serial or USB connection?
If you told it that you have a USB connection then it will be working in USBExpress and WD can’t use the data from it, it needs to have Serial selected. If this is the case then there’s a thread in the FAQ section about it. 