MultiSite has suddenly begun generating 404 errors

Yesterday when I was working in the Themeco Pro theme editing the header, both the main site and the second site began displaying 404 errors for all of the pages and for the theme options. I have removed and reinstalled the theme but still the 404 errors persist. I have turned off compression and zlib in cPanel. There are not any errors displaying in the error log. I remember using a plugin called domainer when setting the multisite up. I do not see that plugin listed any longer. Is domainer required for WordPress/WooCommerce multisite? What else could suddenly cause 404 errors for all of the pages and theme options?
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