2017 iMac, i cannot access secure web pages. I have tried with both safari and Firefox browzers. Any suggestions?

Thanks,

I think I figured out part of the problem. Some how my cookie settings got changed in both browzers to not accepting any cookies. After resetting cookies, Safari started working just fine. I still have few issues in Firefox.

Thanks for the response. But I am not getting a warning, I am getting a blank page, or an endless loop of enter you passsword pages with nothing. This is happening on a number of different sites. All this was working ok a few weeks ago. I am trying to pay online bills. All the same sites work fine when I pay online thru my phone. I have tried with both safari and Firefox browzers. Same problem on both.

Thank you for any help