diff --git a/lib/datasource/npm.js b/lib/datasource/npm.js
index 53131c9850c7baeb9e6a9846c1d64d2eaf17d7ca..70bb2a9a9780ee9c97649fb954dca2a3adb4283b 100644
--- a/lib/datasource/npm.js
+++ b/lib/datasource/npm.js
@@ -31,6 +31,16 @@ function resetCache() {
   resetMemCache();
 }
 
+function maskToken(token) {
+  // istanbul ignore if
+  if (!token) {
+    return token;
+  }
+  return `${token.substring(0, 2)}${new Array(token.length - 3).join(
+    '*'
+  )}${token.slice(-2)}`;
+}
+
 function setNpmrc(input, exposeEnv = false) {
   logger.debug('setNpmrc()');
   if (input) {
@@ -39,10 +49,7 @@ function setNpmrc(input, exposeEnv = false) {
     // istanbul ignore if
     if (npmrc && npmrc[tokenKey]) {
       const token = npmrc[tokenKey];
-      const maskedToken = `${token.substring(0, 2)}${new Array(
-        token.length - 3
-      ).join('*')}${token.slice(-2)}`;
-      logger.debug(`Setting authToken to ${maskedToken}`);
+      logger.debug(`Setting authToken to ${maskToken(token)}`);
     }
     if (!exposeEnv) {
       return;
@@ -150,7 +157,14 @@ async function getDependency(name, retries = 5) {
   } catch (err) {
     if (err.statusCode === 401 || err.statusCode === 403) {
       logger.info(
-        { err, statusCode: err.statusCode, name },
+        {
+          pkgUrl,
+          authInfoType: authInfo ? authInfo.type : undefined,
+          authInfoToken: authInfo ? maskToken(authInfo.token) : undefined,
+          err,
+          statusCode: err.statusCode,
+          name,
+        },
         `Dependency lookup failure: unauthorized`
       );
       return null;
diff --git a/test/manager/npm/registry.spec.js b/test/manager/npm/registry.spec.js
index 6a4089c2a4d9e74dc64975ad350a1ec8f2a58688..2091aa0f5ceb0e69179fdc52f5a82d2b70bb3656 100644
--- a/test/manager/npm/registry.spec.js
+++ b/test/manager/npm/registry.spec.js
@@ -187,6 +187,7 @@ describe('api/npm', () => {
     expect(res).toMatchSnapshot();
   });
   it('should cache package info from npm', async () => {
+    npm.setNpmrc('//registry.npmjs.org/:_authToken=abcdefghijklmnopqrstuvwxyz');
     nock('https://registry.npmjs.org')
       .get('/foobar')
       .reply(200, npmResponse);