The question is on-topic. It is about why Gmail displays some warning and how to avoid that:
What can I do about it? Is there any known source of Gmail's "knowledge" or some official ratings which leads Gmail to such decision (on whether to display such warining or not)? Or is it -- as always -- some internal, unpublished Google's algorithm and I must learn to live with this.
It's not about WordPress development. It's not about administering websites. It's about the Gmail website, which is on-topic here.
Since the question got removed by the automated deletion script as a result of its closure by a moderator, I voted to undelete.
To reply to arguments made by the other answer:
If you are no longer interested in the question consider you might delete it, as it doesn't help anyone that a question like this one as its current state stay sit there for years without any progress update
The question allows other users who may know the answer to post the answer. There's already a script to automatically delete questions with no answers. If you disagree with that script, you can raise the issue on Meta SE.
You might remove the mention that you are the sender of the links and remove wordpress. Questions should not include chitchat and tags should be about what is being asked not about the words included in the question.
That's really not a reason to close. Just make an edit if that's really an issue.