diff --git a/packages/network/lib/agent.ts b/packages/network/lib/agent.ts
index fb65a1b57e1f..425c3605be24 100644
--- a/packages/network/lib/agent.ts
+++ b/packages/network/lib/agent.ts
@@ -38,7 +38,7 @@ export function buildConnectReqHead (hostname: string, port: string, proxy: url.
   connectReq.push(`Host: ${hostname}:${port}`)
 
   if (proxy.auth) {
-    connectReq.push(`Proxy-Authorization: basic ${Buffer.from(proxy.auth).toString('base64')}`)
+    connectReq.push(`Proxy-Authorization: Basic ${Buffer.from(proxy.auth).toString('base64')}`)
   }
 
   return connectReq.join(CRLF) + _.repeat(CRLF, 2)
diff --git a/packages/network/test/unit/agent_spec.ts b/packages/network/test/unit/agent_spec.ts
index 46c451a68b75..b047a23eebca 100644
--- a/packages/network/test/unit/agent_spec.ts
+++ b/packages/network/test/unit/agent_spec.ts
@@ -608,7 +608,7 @@ describe('lib/agent', function () {
       expect(head).to.eq([
         'CONNECT foo.bar:1234 HTTP/1.1',
         'Host: foo.bar:1234',
-        'Proxy-Authorization: basic YmF6OnF1dXg=',
+        'Proxy-Authorization: Basic YmF6OnF1dXg=',
         '', '',
       ].join('\r\n'))
     })