This is a Windows-only problem.

Logger Pro requires Bluetooth radios that use the Microsoft driver. Some third-party drivers will allow Logger Pro to see the WDSS, but will not work properly to provide data communication. For these drivers, you’ll see the following symptoms:

Launch Logger Pro.
Turn on a fully-charged WDSS.
Choose Connect Interface –> Wireless –> Scan for Wireless Devices from the Experiment menu.
Logger Pro scans for a while–possibly requiring several rescans (normal for Windows).
Logger Pro displays a dialog where you can see and choose the WDSS by name. In other words, Logger Pro definitely sees your particular WDSS.
You click to connect, and Logger Pro immediately displays a dialog stating that Logger Pro could not connect to the WDSS, and suggests steps for troubleshooting.

If this happens, then it is very likely that you have a non-Microsoft driver, made by Broadcom (aka WIDCOMM), installed for your bluetooth radio.

The solution is to remove the 3rd-party driver, and install the Microsoft driver.

There are steps available at

https://www.vernier.com/bthelp/#remove_driver

to assist you in removing the non-MS driver. Unfortunately we cannot write exact steps for all non-MS drivers, since their behavior and appearance will vary with publisher and release version.