404 error 9.4

Hopefully someone can help.

I read the other post on this and tried to get the 404 to work without success.

I changed companies for servers and now would like to have a 404 to work with the old .shtml or any other error in url to point to the new Contao site.

I continue to get the standard error from the hosting company.

I have other sites hosted under the shared hosting and was wondering if that is an issue. I have been working on the .htaccess.default and didn't know if this is the issue.

Thanks for all help

Thanks