Hi @bpsubp
I have checked the sitemap URL and noticed it is showing “error on line 2 at column 6: XML declaration allowed only at the start of the document“.
Conflict check:
There is an empty space or a blank line before or after the closing PHP opening or closing tag, which shouldn’t be there. An empty whitespace or a blank line appears due to a conflict with another plugin or your theme.
You can narrow down the exact source of conflict by performing a conflict check. Please test this on your development or staging site if you have one. If not, we recommend using the Health Check & Troubleshooting plugin. This plugin has a troubleshooting mode, which does not affect normal visitors to your site.
Often, we see problems occur in combination with another plugin or theme. The fastest way to rule out any conflict is to deactivate all non-Yoast plugins and switch to a standard theme like Twenty Twenty-Two when you are in troubleshooting mode.
If you’re unfamiliar with checking for conflicts, we’d like to point you to a step-by-step guide that will walk you through the process: How to check for plugin conflicts
Once you have identified whether your theme or a plugin causes the issue, please contact the developers of that theme or plugin for assistance in finding and removing the white space.
