In Safari credit card account sites not opening

What OS version?

See if anything here helps.

Block cookies is off but being limited by… - Apple Community

Are you running any anti - virus programs? Using a VPN?

Try setting up another admin user account in System Preferences/Users & Groups to see if the same problem continues. Also try the Safe Mode. 

Isolating an issue by using another user account   

Safe Mode - About.       

If it works in the Safe Mode, try running this program when booted normally and then copy and paste the output in a reply. The program was created by Etresoft, a frequent contributor.  Please use copy and paste as screen shots can be hard to read. Click “Share Report” button in the toolbar, select “Copy to Clipboard” and then paste into a reply. This will show what is running on your computer. No personal information is shown. If the log won’t post, try posting it in Pastebin and provide a link in a reply. After pasting the report in a PasteBin page, go to the top of the page, and copy the address in the URL bar. Paste that in a new reply.        Pastebin.    

Etrecheck – System Information.      

Web site version if required.  https://etrecheck.com

Hello Cad2010,

Thanks for using Apple Support Communities.

We understand you are experiencing some issues with opening certain sites in Safari. We are happy to go over this with you and get it working again.

Let's take a look at these helpful resources regarding issues with opening certain websites within Safari to see if it clears this issue up:

If Safari doesn't load a page or webpage items are missing

If you can’t open a website in Safari on Mac

If the issue continues, we would like to ask some questions to get a better understanding of what is happening.

1.) If you use a different browser on your device, such as Google Chrome, do those websites open without issue?

2.) Are you using a Wi-Fi or ethernet connection to connect to the internet?

3.) If you connect your device to a different Wi-Fi connection and try to access those sites, do they those websites open?

Let us know how it goes and the answers to those questions if it continues.

Cheers.