diff --git a/lib/server.js b/lib/server.js
index ea733c0..aac126f 100644
--- a/lib/server.js
+++ b/lib/server.js
@@ -181,7 +181,7 @@ const [
       this.raw.write(`id: ${this.message_count++}\n${event ? `event: ${event}\n` : ''}data: ${JSON.stringify(payload)}\n\n`)
     })
 
-  const channelsBlocked = new Set(process.env.BLOCKED_CHANNELS ? process.env.BLOCKED_CHANNELS.split(',') : [])
+  const channelsBlocked = new Set((process.env.BLOCKED_CHANNELS || '').split(','))
 
   const channelsBlockedHandler = channelsBlocked.size !== 0
     ? (req, reply, done) => {