From my experience, an instrument should be capable of communication/control even with this exclamation present, but this does mean there is a ‘warning’ with the overall connection. However, there are a few things to try to resolve this warning.
Ensure that the device (instrument, MSO44) is found/discoverable within Device manager.
1. Connect the scope to the computer using the ‘Device Port’ on the back of the instrument (MSO44). Connect this to a Host Port on your PC.
2. Device Manager -> USB Test and Measurement Devices -> USB Test and Measurement Devices (IVI).
3. Be sure to update drivers if this is needed.
My next suggestion would be to uninstall all VISAs currently installed on the computer connecting with the MSO44. Then reinstall TekVISA first, and NI-Visa Second.
1. Uninstall all VISAs from computer (TekVISA, and all other VISAs).
2. Install TeKVISA - TEKVISA Connectivity Software - V4.2.0: https://www.tek.com/en/support/software/driver/tekvisa-connectivity-software-v420
3. Install NI-VISA -V21.5: https://www.ni.com/en-us/support/downloads/drivers/download.ni-visa.html#442805
After you have performed the steps above, see if you can send a *IDN? Command to the instrument (MSO$$) via Tektronix VISA Resource Manager or NI-MAX. If so, attempt to send the same *IDN? Command within Labview.
If possible, I would suggest connecting/communicating with the MSO44 via ethernet instead of USB. While USB does provide a stable connection, I have found that Ethernet is the most Efficient and effective method for remote operation/control of the instrument through programable commands (SCPI) or E*Scope. I understand that this is not always a possibility.