thank you for your reply.
SO I've restricted one API key by IP. I've inserted this in the first field in Toolset>Maps>Google Map API key, and the other API key restricted by domain in the second field. It's still showing the error "REQUEST_DENIED - API keys with referer restrictions cannot be used with this API".
What am I supposed to do? I cannot switch them cause the one restricted by domain is not accepted in the first field..
If I remove the second one another error shows up: "REQUEST_DENIED - This IP, site or mobile application is not authorized to use this API key. Request received from IP address 35.214.254.216, with referer: -there's a link here with the Key-".
So I'm now wondering: which IP address should I insert when creating the key? I used my website IP address, but maybe that's wrong?!.
Could you tell me exactly where to insert which key please?
It may take sometime with google to restrict the IP entries - can you please check back after sometime.
OR
You can check with google map support to check why IP based restriction is not working.
Maybe it will be great if you can get in touch with google map support and check with them what is the best practice in your case and how you can restrict it and by creating what restriction.
Thank you Minesh.
I've followed all the guidelines provided by Google Cloud Platform but still it wasn't working.
Their support is not available for free so I'll have to check with the CLient.