"server is requesting basic authentication without a secure connection"

I've just run into something that I've never seen before, and I know the answer will be here...

I've turned into a online genealogy addict, and I found a site that promises overflowing databases of some difficult to locate/access info

the database is password controlled, had to get a user ID and password from the site owner... which I did..
have to use IE to access the database... which I did

THIS is the message box that resulted from my attempt to log in:

Warning: This server is requesting that your username and password be sent in an insecure manner (basic authentication without a secure connection)​

three tries to log in, and them back to the site's "register for a user id" page...

WTH?:confused

site owner response to my Q "no idea.. problem on your end... need IE browser"

what's the deal?
should I just kiss off this dream database as a possible nitemare??
(connecting to net via DSL Cable modem/wireless router)

as I said, NEVER since I went online in 2000 have I run into this...

thanks MG!:major
mb