diff --git a/src/node/handler/PadMessageHandler.js b/src/node/handler/PadMessageHandler.js
index 214571044..84ec9b5c1 100644
--- a/src/node/handler/PadMessageHandler.js
+++ b/src/node/handler/PadMessageHandler.js
@@ -1124,20 +1124,25 @@ async function handleClientReady(socket, message, authorID) {
       if (sessionInfo == null) return;
 
       // get the authorname & colorId
-      const author = sessionInfo.author;
-      const cached = historicalAuthorData[author];
+      const authorId = sessionInfo.author;
+      // The authorId of this other user might be unknown if the other user just connected and has
+      // not yet sent a CLIENT_READY message.
+      if (authorId == null) return;
 
       // reuse previously created cache of author's data
-      let authorInfo = cached ? cached : (await authorManager.getAuthor(author));
+      const authorInfo = historicalAuthorData[authorId] || await authorManager.getAuthor(authorId);
+      if (authorInfo == null) {
+        messageLogger.error(
+            `Author ${authorId} connected via socket.io session ${roomSocket.id} is missing from ` +
+            'the global author database. This should never happen because the author ID is ' +
+            'generated by the same code that adds the author to the database.');
+        // Don't bother telling the new user about this mystery author.
+        return;
+      }
 
       // default fallback color to use if authorInfo.colorId is null
       const defaultColor = '#daf0b2';
 
-      if (!authorInfo) {
-        console.warn('handleClientReady(): no authorInfo parameter was received. Default values are going to be used. See issue #3612.  This can be caused by a user clicking undo after clearing all authorship colors see #2802');
-        authorInfo = {};
-      }
-
       // For some reason sometimes name isn't set
       // Catch this issue here and use a fixed name.
       if (!authorInfo.name) {
@@ -1162,7 +1167,7 @@ async function handleClientReady(socket, message, authorID) {
             colorId: authorInfo.colorId,
             name: authorInfo.name,
             userAgent: 'Anonymous',
-            userId: author,
+            userId: authorId,
           },
         },
       };