how to permanently remove gsecurecontent.com popups from safari

Greetings Grodr,

We'd like to provide you with a few steps that can assist you with the pop-up that keeps occurring while using Safari:

"Avoid interacting with pop-ups

Unless you’re confident that they are a legitimate ad, avoid interacting with pop-ups or webpages that seem to take over your screen.

• If you see an annoying pop-up ad in Safari, you can go to the Search field and enter a new URL or search term to browse to a new site. If you don’t see the Search field on your iPhone or iPad, tap the top of the screen to make it appear.
• Some pop-ups and ads have fake buttons that resemble a close button, so use caution if you try to close a pop-up or ad. If you're not sure, avoid interacting with it and close the Safari window or tab.
• On your Mac, you can quit Safari, then press and hold the Shift key while opening Safari. This prevents Safari from automatically reopening any windows or tabs that were open. 

Update your software

Always install the latest software updates for all of your Apple products. Many software releases have important security updates and may include improvements that help control pop-ups.

The safest way to download apps for your Mac is from the App Store. If you need software that isn’t available from the App Store, get it directly from the developer or another reliable source, rather than through an ad or link.

Check Safari settings

On your iPhone or iPad, go to Settings > Safari.

• Turn on Block Pop-ups.
• Turn on Fraudulent Website Warning.

On your Mac, open Safari and choose Safari > Settings (or Preferences) from the menu bar.

• In the Websites tab, you can configure options to allow or block some or all pop-ups.
• In the Security tab, turn on the setting to warn when visiting a fraudulent website.

If adware or other unwanted software is installed on Mac

If you see pop-ups on your Mac that just won’t go away, you might have unintentionally downloaded and installed adware (advertising-supported software) or other unwanted software. Certain third-party download sites might include software that you don’t want along with the software that you do.

If you think that you might have malware or adware on your Mac:

• Update to the latest version of macOS. If your Mac is already using the latest version, restart your Mac. macOS includes a built-in tool that removes known malware when restarting.
• Check your Applications folder to see if you have any apps that you don't expect. You can uninstall those apps.
• Check the Extensions tab in Safari settings to see if you installed any unnecessary extensions. You can turn extensions off.

If you continue to see advertising or other unwanted programs on your Mac, contact Apple."

More details here: Block pop-up ads and windows in Safari

Thanks for posting in Apple Support Communities.

Best regards.

Please read Removing "Search Marquis" / "Search Baron" / etc on your own - Apple Community, and post the three screenshots it describes in a reply to this Discussion.