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@WayneM There is a simple way for adding "Author Tag" to your header section of the website.
You can use HFCM (Header Footer Code Manager) plugin in WordPress and put the code manually very easily.

And one more thing, HFCM plugin is safe and reliable. You can use it without any worry.

Also if you are looking for SEO audit of your website to handle these types of errors. Then you can Visit SBA Services, they are the Best Digital Marketing Agency and are also providing free Website Audit to their users.
Thanks!

A sudden increase in spam score from 1% to 31% overnight could be attributed to various factors, such as an

• Influx of spammy backlinks

• Content changes that mimic spam characteristics

• list itemA potential hacking incident leading to malicious content
  Conduct a thorough backlink analysis, review recent site changes, and perform security checks to identify and address the specific issues causing the spike in spam score.

Also if you want your whole website audit for free. You can visit at SBA Services one of the best Digital Marketing Agency and get your audit done to know what can you improve your site.
Thanks