Hi there PACODOLZ,
Check out the steps below, which may help you successfully log in and load that website again in Safari:
"Reload the page
To reload a page, choose View > Reload Page, or press Command-R. If you can't reload, make sure that you're connected to the internet.
If you still can't reload:
- Press Command-Q to quit Safari. If Safari doesn't quit, press Option-Command-Esc to force Safari to quit.
- Open Safari again and try to load the page. When Safari opens, if it automatically opens pages that you don't want to open, quit Safari again, then press and hold the Shift key while opening Safari.
Check Safari extensions
If you installed any Safari extensions, make sure that they are up to date.
You can also try turning extensions off. From the menu bar in Safari, choose Safari > Settings (or Preferences). Click Extensions, then deselect the checkbox for each extension to turn it off. Learn more about Safari extensions."
Those steps, and additional steps to try if the ones above don't help, can be found in this article: If Safari on Mac doesn't open a webpage or isn’t working as expected - Apple Support
Please let us know if that helps or if you've already tried the steps in that article, as it can help determine possible next steps.
Take care!