Help to locate ad pop-up code that I've never installed, I suspect some hack

Hi

website: https://www.thetechgears.com

Thanks for your support for my last issue. I have a different question now, a pop-up window opens up in the site leading to perfectmatch.com, but I am sure I haven’t installed any ad-code, especially pop-up of this kind. I tried to figure out the location of the code but failed.

While the pop-up loads I could see some URL like anrdoezrs.net loads up, this could be a hint in tracing

Is the code located within database? or somewhere else?, kindly help me in this regard

Thanks in advance