Header error b/c of no www prefix.

Hello!

Firstly, thank you very much for looking into this.

Secondly, my situation is this:

I have a WP installation in its own sub-dir on my server. I also have the the index.php and .htaccess files moved to the root dir. As you may expect, I did this so that my blog can be accessed by https://www.domain.com or domain.com.

Now, regardless of whether I choose the blog’s domain to have or not have the www domain prefix, whatever the URL is not set to in the settings panel in the Dashboard… will bring up an error.

For example, if in the WordPress Address box I have: https://www.domain.com/blog and then in the Blog Address box I have https://www.domain.com, going to https://www.domain.com works fine. However, going to domain.com brings up the following error:

Warning: Cannot modify header information – headers already sent by (output started at /home/content/i/n/d/indecisiveian1/html/index.php:1) in /home/content/i/n/d/indecisiveian1/html/blog/wp-includes/pluggable.php on line 850

Now, I’ve looked for any extra spaces in the index.php file… haven’t found any. I’m not sure how to rectify this situation.

Essentially, I would like to have the site accessible at either url, which would mean I need a redirect of some kind. I’ve tried different approaches with the .htaccess file, but have had the same error pop up, so I reverted it to the default.

Help! I implore you!