如何使用php从电子邮件中获取@符号后的数据

Question

i am trying to get the data After an '@' sign from an email address, this is what i am trying to do i am using the $_GET['email'] to get the email from the url, now i want to extract the data after the @, store the data in a variable then send the user to that domain eg: [e-mail] i want to get the gmail.com, store it and then send the user to gmail.com

this is all i have tried but all gives me the same error 1:

    $domain1 = $_GET['email'];    
    $domain = substr($domain1, strpos($domain1, "@") + 1); 
    // then am using the header location to send the user to the gmail.com
    header('Location: http://$domain');

2:

       $domain1 = $_GET['email'];
       $domain2 = strtok( $domain1, '@' );
       $domain = strtok( '' ); 
       // then am using the header location to send the user to the gmail.com
       header('Location: http://$domain');

this is the error

This site can’t be reached %24domain’s server IP address could not be found.
Try running Windows Network Diagnostics.
DNS_PROBE_FINISHED_NXDOMAIN

if you read the error message it is trying to redirect to %24domain and i don't know where its getting that from

i have tried all the Technics related to this i saw from this forum but i still get the same error

guys please help