Hi Helix58
In addition to the suggestions and linked document that alma 1090 provided, if you are on a home broadband network and have not already done so, reboot your modem/router.
For most home networks this will reset your modem/router’s internal firewall, which may have blocked the transport ports necessary to login to your website, and also assign a different internet address to your router, which may overcome a block on your current internet address being imposed by the site you are trying to reach.
Although not strictly relevant in this case, because your other devices on the same network can reach the site, a final reason to reboot your modem/router is that occasionally your ISP will change the address of the DNS server(s) that are used to find the site you are trying to connect to, when this happens you may be redirected to a cached web page and not the current “live” page. When you reboot your modem/router it will automatically be assigned the address of the your ISP’s current DNS server(s).
Organisations large and small, that operate their own internal IT infrastructure, reboot their servers, routers and other internet facing equipment regularly to avoid this problem and most home modem/routers have the option to do this for you on a regular timed schedule, once per week, during the night, would be beneficial for most home users. Check under the advanced options for your modem/router for this facility and if available make use of the scheduled reboot function.
I notice that you state you cleared Safari caches on your MacBook, how did you do this, was it through the Develop menu?
The Develop menu provides a direct method of clearing Safari caches that goes deeper than just clearing internet history and web data through the normal user menu History > Clear History…
If you have not tried the Empty Caches method from the Develop menu follow these steps:
In Safari Preferences click Advanced, at the bottom of the page enable the option “Show Develop menu in the menu bar” to add the Develop menu to the Safari menu ribbon. Close the preferences panel.
With Safari open look for the new menu on the Safari menu-ribbon (at the top of the desktop), click on the Develop menu then scroll down and click on the command, “Empty Caches”, alternatively, with Safari open press the following keys simultaneously
Option + Command + E.
Then close Safari and restart your MacBook.
After this step are you now able to connect and log in to the website you wish to enter?
Finally, if none of the steps suggested help, either in the linked document provided by alma 1090, or those above, boot your MacBook into Safe-Mode and see if you can make a connection and log-in using Safari while in Safe-Mode.
If yes, exit Safe-Mode and try again after a restart back into Normal-Mode.
Please be patient when booting into Safe-Mode, this takes a while and your computer will seem sluggish, this is normal.
Review this linked document for an explanation of Safe-Mode and how to access it:
https://support.apple.com/en-gb/HT201262
HTH.
Will.
