Prevents WordFence from scanning

When this plugin is active, it prevents WordFence from scanning. I get the following error message:

“a scan stage has failed to start. this is often because the site either cannot make outbound requests or is blocked from connecting to itself. wordfence will make up to 2 attempts to resume each failed scan stage. this scan may recover if one of these attempts is successful.”

Something in the plugin is preventing WordFence from connecting to the WordPress server.