Problem with a s4

[AC Question]

Hi i have a Samsung galaxy s4.
Sometimes the phone will run very slow and even vibrate for no reason.
I then restart the phone and get a notification of a missed call. I have asked my friend if they tried calling and they have not.
I also get redirected to another page about viruses when looking on gumtree webpage

 

[belodion]

Does all this persist in Safe Mode?

 

[Whiteknight272]

Safe mode as in off line?