Vista - I cannot sign on to several of my paid websites . . .

I have several paid websites that I use daily. I never had a problem before
with XP in signing on to these sites.
I tried to get into them today, and the error message told me I had to sign
on in an unsecure fashion, or something about a spam filter.
What do I have to do to accomplish this? I'm not that savvy when it comes
to this type of thing.
Can anyone help?

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debarybabs