Hello, thanks again for your response.
The IP is not listed in blacklists.
We also have other websites hosted on the server without any being marked/listed with problems.
The only thing that occurs to me, is that the latest functionality we've included, for send webpush notifications, will trigger the false positive. An Ajax call is made to re-subscribe the users in the background. But I'm not sure about anything and no one has given us an explanation. The systems for analysis create a positive and do not know the reasons? All this seems very strange to me, really.
Thank you,
Miguel.