Hello,
Thanks for reaching out! I'm Microsoft user like you.
To view current network connection, type command net use
C:> net use
Possibly that your other colleague may have login before or his credential may used by somebody so Windows will pop-up from cache.
Click Start > Control Panel > User Accounts > Credential Manager -> Select the Windows Credentials -> Try to find unwanted Credentials -> Click Remove.
Best Regards,
Prakash