I am getting an error message in the domain mapping page of the dashboard

This is the message i'm getting:

Parse error: syntax error, unexpected T_STATIC in /home/content/31/8351131/html/LaramieRadio/wp-content/plugins/domain-mapping/classes/Vendor/Punycode.php on line 75

My sites are becoming unresponsive. Sometimes I will go to one of them and it works ok and then a few minutes later it will time out and back and forth we go