Device Cannot Find any WIFI networks

Hello,

i own a Samsung Galaxy S3 mini for the past 2 years and i did not have any problems with it. Suddenly 2 days ago the wifi signal started to drop every 15 minutes and i could not connect to the internet. I decided to do a factory reset to fix the issue.

After the reset the device could not find any wifi networks to connect to. Do you have any idea what is problem?

Thank you very much !