https://support.wix.com/en/article/troubleshooting-your-adstxt-file-for-google-adsense
Although as it states on that page, it is an app and not really part of Wix Corvid, of which this forum is supposed to be used for.
***After adding the Google AdSense app, Wix automatically generates an Ads.txt file for your site. ***
So you might be better suited going through Wix Support themselves.
https://support.wix.com/en/about-wix/contacting-wix-support