diff --git a/docs/releases.md b/docs/releases.md
index 3034980..b6f267e 100644
--- a/docs/releases.md
+++ b/docs/releases.md
@@ -6,6 +6,8 @@ and the [ntfy Android app](https://github.com/binwiederhier/ntfy-android/release
 
 This release changes the way UnifiedPush (UP) topics are rate limited from publisher-based rate limiting to subscriber-based
 rate limiting. This allows UP application servers to send higher volumes, since the subscribers carry the rate limits.
+However, it also means that UP clients have to subscribe to a topic first before they are allowed to publish. If they do
+no, clients will receive an HTTP 507 response from the server.
 
 We also fixed another issue with UnifiedPush: Some Mastodon servers were sending unsupported `Authorization` headers, 
 which ntfy rejected with an HTTP 401. We now ignore unsupported header values. 
diff --git a/server/log.go b/server/log.go
index d385821..0425768 100644
--- a/server/log.go
+++ b/server/log.go
@@ -30,6 +30,10 @@ const (
 	tagMatrix       = "matrix"
 )
 
+var (
+	normalErrorCodes = []int{http.StatusNotFound, http.StatusBadRequest, http.StatusTooManyRequests, http.StatusUnauthorized, http.StatusInsufficientStorage}
+)
+
 // logr creates a new log event with HTTP request fields
 func logr(r *http.Request) *log.Event {
 	return log.Tag(tagHTTP).Fields(httpContext(r)) // Tag may be overwritten
diff --git a/server/server.go b/server/server.go
index 4be299f..50a4723 100644
--- a/server/server.go
+++ b/server/server.go
@@ -319,19 +319,21 @@ func (s *Server) handleError(w http.ResponseWriter, r *http.Request, v *visitor,
 	if !ok {
 		httpErr = errHTTPInternalError
 	}
-	isNormalError := strings.Contains(err.Error(), "i/o timeout") || util.Contains([]int{http.StatusNotFound, http.StatusBadRequest, http.StatusTooManyRequests, http.StatusUnauthorized}, httpErr.HTTPCode)
+	isNormalError := strings.Contains(err.Error(), "i/o timeout") || util.Contains(normalErrorCodes, httpErr.HTTPCode)
+	ev := logvr(v, r).Err(err)
 	if websocket.IsWebSocketUpgrade(r) {
+		ev.Tag(tagWebsocket).Fields(websocketErrorContext(err))
 		if isNormalError {
-			logvr(v, r).Tag(tagWebsocket).Err(err).Fields(websocketErrorContext(err)).Debug("WebSocket error (this error is okay, it happens a lot): %s", err.Error())
+			ev.Debug("WebSocket error (this error is okay, it happens a lot): %s", err.Error())
 		} else {
-			logvr(v, r).Tag(tagWebsocket).Err(err).Fields(websocketErrorContext(err)).Info("WebSocket error: %s", err.Error())
+			ev.Info("WebSocket error: %s", err.Error())
 		}
 		return // Do not attempt to write to upgraded connection
 	}
 	if isNormalError {
-		logvr(v, r).Err(err).Debug("Connection closed with HTTP %d (ntfy error %d)", httpErr.HTTPCode, httpErr.Code)
+		ev.Debug("Connection closed with HTTP %d (ntfy error %d)", httpErr.HTTPCode, httpErr.Code)
 	} else {
-		logvr(v, r).Err(err).Info("Connection closed with HTTP %d (ntfy error %d)", httpErr.HTTPCode, httpErr.Code)
+		ev.Info("Connection closed with HTTP %d (ntfy error %d)", httpErr.HTTPCode, httpErr.Code)
 	}
 	w.Header().Set("Content-Type", "application/json")
 	w.Header().Set("Access-Control-Allow-Origin", s.config.AccessControlAllowOrigin) // CORS, allow cross-origin requests