diff --git a/src/api/v0/index.js b/src/api/v0/index.js
index b43dbeb..32c7764 100644
--- a/src/api/v0/index.js
+++ b/src/api/v0/index.js
@@ -327,7 +327,7 @@ router.get('/profile/fetch',
     }
 
     if (data.errors.length > 0) {
-      delete data.key
+      data.key = undefined
       res.status(500).send(data)
     }
 
@@ -335,7 +335,7 @@ router.get('/profile/fetch',
     if (req.query.returnPublicKey) {
       data.keyData.key.data = data.key.publicKey
     }
-    delete data.key
+    data.key = undefined
 
     // Do verification
     if (req.query.doVerification) {
diff --git a/src/api/v2/keyoxide_profile.js b/src/api/v2/keyoxide_profile.js
index cf6c08b..f13a7c2 100644
--- a/src/api/v2/keyoxide_profile.js
+++ b/src/api/v2/keyoxide_profile.js
@@ -298,7 +298,7 @@ router.get('/fetch',
     }
 
     if (data.errors.length > 0) {
-      delete data.key
+      data.key = undefined
       res.status(500).send(data)
     }
 
@@ -306,7 +306,7 @@ router.get('/fetch',
     if (req.query.returnPublicKey) {
       data.keyData.key.data = data.key.publicKey
     }
-    delete data.key
+    data.key = undefined
 
     // Do verification
     if (req.query.doVerification) {
diff --git a/src/api/v2/proxy_get.js b/src/api/v2/proxy_get.js
index e31e992..5cacfa6 100644
--- a/src/api/v2/proxy_get.js
+++ b/src/api/v2/proxy_get.js
@@ -118,9 +118,7 @@ router.get(
   query('id').isEmail(),
   async (req, res) => {
     if (
-      !opts.claims.xmpp.service ||
-      !opts.claims.xmpp.username ||
-      !opts.claims.xmpp.password
+      !((opts.claims.xmpp.service && opts.claims.xmpp.username) && opts.claims.xmpp.password)
     ) {
       return res.status(501).json({ errors: 'XMPP not enabled on server' })
     }
@@ -166,7 +164,7 @@ router.get(
   query('roomId').isString(),
   query('eventId').isString(),
   async (req, res) => {
-    if (!opts.claims.matrix.instance || !opts.claims.matrix.accessToken) {
+    if (!(opts.claims.matrix.instance && opts.claims.matrix.accessToken)) {
       return res.status(501).json({ errors: 'Matrix not enabled on server' })
     }
     const errors = validationResult(req)
diff --git a/src/server/index.js b/src/server/index.js
index e247f99..b92240d 100644
--- a/src/server/index.js
+++ b/src/server/index.js
@@ -151,7 +151,7 @@ const generateSignatureProfile = async (signature) => {
     .then(async key => {
       let keyData = key.keyData
       keyData.openpgp4fpr = `openpgp4fpr:${keyData.fingerprint.toLowerCase()}`
-      delete key.keyData
+      key.keyData = undefined
       keyData.key.data = {}
       keyData = processKeyData(keyData)
 
diff --git a/src/server/keys.js b/src/server/keys.js
index 793e1b4..474efab 100644
--- a/src/server/keys.js
+++ b/src/server/keys.js
@@ -49,7 +49,7 @@ const fetchWKD = (id) => {
       }
 
       const [, localPart, domain] = /([^@]*)@(.*)/.exec(id)
-      if (!localPart || !domain) {
+      if (!(localPart && domain)) {
         reject(new Error(`The WKD identifier "${id}" is invalid`))
       }
       const localEncoded = await computeWKDLocalPart(localPart)