ExoClick is a legitimate ad network for adult websites, but Google may find some of their ads questionable, so I have disabled them.
This article from ExoClick themselves is why I believe one of their ads was the culprit.
ExoClick and Malware and Google ad compliance - ExoClick
This is the end of Javascript ads here. I cannot trust these companies, even if it was just one ad with malware that slipped through the cracks, one is all it can take with Google. They are quick to label a site as potentially dangerous, but they are always slow to investigate.
From now on, I'll either do simple animated banner ads or e-begging. (by me a coffee )
I'm no fan of Google, but there's nothing suspicious about what happened. Google found something they thought was a security issue and flagged the site, as they should. It can take a while for this to resolve itself. It may take several days or weeks to review the issue.
https://support.google.com/webmasters/answer/9044101#links_to_harmful_downloads&zippy=%2Clinks-to-harmful-downloads