Who are bgiftbrusselsairlines?

Sounds like a scam.

Learn how to identify and avoid fraudulent "phishing" email, fake ‘virus alerts’ and other scams:

https://support.apple.com/en-us/ht204759

How to report phishing emails to Apple:

These email addresses are monitored by Apple, but you might not receive a reply to your report.

• If you receive what you believe to be a phishing email that's designed to look like it’s from Apple, please send it to reportphishing@apple.com.
• To report spam or other suspicious emails that you receive in your iCloud.com, me.com, or mac.com Inbox, please send them to abuse@icloud.com.
• To report spam or other suspicious messages that you receive through iMessage, tap Report Junk under the message, or take a screenshot on your iPhone, iPad, iPod touch, or Mac and send it to imessage.spam@apple.com.
• If you receive a suspicious message about your purchase activity in the iTunes Store, App Store, or iBooks Store, contact iTunes Support.

Safari/Preferences/Advanced - enable the Develop menu, then go there and Empty Caches. Quit/reopen Safari and test. Then try Safari/History/Show History and delete all history items. Quit/reopen Safari and test. You can also try try Safari/Clear History…. The down side is it clears all cookies. Doing this may cause some sites to no longer recognize your computer as one that has visited the web site. Go to Finder and select your user/home folder. With that Finder window as the front window, either select Finder/View/Show View options or go command - J. When the View options opens, check ’Show Library Folder’. That should make your user library folder visible in your user/home folder. Select Library/Caches/com.apple.Safari/Cache.db and move it to the trash.

Go to Safari Preferences/Extensions and turn all extensions off. Test. If okay, turn the extensions on one by one until you figure out what extension is causing the problem.

If that doesn't work, try running this program in your normal user account , then copy and paste the output in a reply. The program was created by etresoft, a frequent contributor. Please use copy and paste as screen shots can be hard to read. On the screen with Options, please open Options and check the bottom 2 boxes before running. Click “Share Report” button in the toolbar, select “Copy Report” and then paste into a reply. This will show what is running on your computer. No personal information is shown.

Etrecheck – System Information