Enter Network Password

While I'm using my Windows 10 laptop (with MS Office 2007) I keep getting a popup labelled "Enter Network Password". Server is pre-filled to be "pop.cox.net" and User is pre-filled to be my Cox username (without @cox.net). I enter my password (which has NOT been recently changed) and check "Save this password in your password list" then click OK. Sometimes that's it or sometimes I get the same prompt again up to 4 or 5 times then it stops for a while but it comes back within 30-60 minutes. I have rebooted the laptop but that didn't seem to help. I am NOT having similar issues on other desktop computers, laptops, iPads, or iPhones - it's only on this one laptop. To be super sure of the password I manually entered it when logging in to get here (vs letting it be pre-filled by the OS or my password mgmt. tool).