Hi springy, what does the error page say? Is it a Constant Contact error page or a Cloudflare error page?

Firefox users may be using Cloudflare for DNS lookups -- this is the service that associates a server's name with its numeric IP address. If you have problems with servers not being found, you can turn that off on the Options page. More info in this article: Firefox DNS-over-HTTPS.

When you first launch a private window, it does not have any data about the site, so it has a fresh cache and fresh cookies. So one possible thing to try -- in regular windows -- would be to clear Firefox's web cache and your cookies for the site:

(1) Clear Firefox's Cache

See: How to clear the Firefox cache (just the web cache, not all site data)

If you have a large hard drive, this might take a few minutes.

(2) Remove the site's cookies (save any pending work first). While viewing a page on the site, click the lock icon at the left end of the address bar. After a moment, a "Clear Cookies and Site Data" button should appear at the bottom. Go ahead and click that.

In the dialog that opens, you will see one or more matches to the current address so you can remove the site's cookies individually without affecting other sites.

Then try reloading the page. Does that help?

Testing in Firefox's Safe Mode: In its Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" Help > Restart with Add-ons Disabled
• (menu bar) Help menu > Restart with Add-ons Disabled

and OK the restart. A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

If Firefox is not running: Hold down the Shift key when starting Firefox. (On Mac, hold down the option/alt key instead of the Shift key.) A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement?

Seems to have worked to clear cache but signing in to the site still takes a trip to Cloudflare screen for no reason I can explain.

A lot of sites use Cloudflare as a content distribution network (CDN); it's actually an option in the control panel for my little site, although I've never tried it. That said, if it's not normal for Constant Contact, I would double-check with them on that to make sure it's okay.

Some webapage are protected by Cloudflare and temporarily show a "checking your browser before accessing" page before redirecting you to the actual webpage. The result of this challenge is stored in a cf_clearance cookie, so if you lose this cookie then you will get this challenge page again or if this challenge fails then you keep getting this challenge page reloading indefinitely. You may want to make sure you keeps such a cookie if you visit the page regularly.

Such a detail is stored in a cookie. You can use these steps to make a website recognize and remember you:

• create a cookie allow exception with the proper protocol (https:// or http://) to make a website remember you

You can check that you aren't clearing important cookies.

• using "Delete cookies and site data when Firefox is closed" keeps cookies with an allow exception
• using "Clear history when Firefox closes" to clear cookies clears all cookies including cookies with an allow exception you may want to keep
• clearing "Site Preferences" clears exceptions for cookies, images, pop-up windows, and software installation and exceptions for passwords and other website specific data

• Options/Preferences -> Privacy & Security
  Cookies and Site Data: "Manage Exceptions/Permissions"