This could be caused by a number of things including some sort of malware. Have you tried running your anti-spyware, anti-malware programs and anti-virus?
Failing that here`s what Ms Community Solutions has to say about it: click here
Nokia 8 vs Galaxy S8
Best new design books 2017: From vintage infographics to the the psychology of type
iMac 21.5-inch (2017) review
Nokia 8 : design, caractéristiques techniques, date de sortie