WebKitErrorDomain:300

SRoss0 wrote:

How do I fix "WebKit encountered an internal error" (WebKitErrorDomain:300)?

You do say what macOS...(?)

Keep your Mac up to date - Apple Support

https://support.apple.com/guide/mac-help/get-macos-updates-mchlpx1065/mac

If Safari on Mac doesn't open a webpage or isn’t working as expected

https://support.apple.com/en-us/HT204098

You can try launching Safari with the Shift key held down for a 'safe launch' of the Safari application..to test

if no resolve or insight

— try booting the machine in SafeBoot Mode:    https://support.apple.com/en-us/HT201262

— try a different browser and compare your results