Hi,
Here is an article which record a similar issue with you, please refer to it and check the measures on your side.
https://www.reddit.com/r/nspire/comments/8fw0j5/cant_connect_tinspire_cx_to_computer/
Note: This is a third-party link and we do not have any guarantees on this website. And Microsoft does not make any guarantees about the content.
Best regards,
Sylvia