VyroAI

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Lost Connection to the Build Service

Your browser stopped hearing back from the build server. The build almost certainly finished anyway — the .jar is waiting in Build History.

What the message means

Your project is compiled on our build server, not in your browser. While it compiles, the browser does one small job: every five seconds it asks the server whether the build has finished.

When those questions stop getting through, the build log prints "Connection to the build service lost — reconnecting…" and the step under the progress bar changes to Reconnecting….

That is a message about the conversation, not about the compile. The build server carries on compiling your project exactly as before — it never needed your browser to be listening.

It reconnects on its own, and the clock is paused

The browser keeps trying. As soon as one of its questions is answered again, the log says "Reconnected to the build service.", the step goes back to Compiling…, and the build finishes normally with its .jar ready to download.

Time lost to an outage is not counted against the build's five-minute window either — up to ten minutes of it is added back — so a shaky connection does not fail a build that was simply taking its time.

When it gives up, it tells you where the .jar is

If the connection never comes back within the window, the build panel turns red and the log ends with:

"Lost connection to the build service. The build likely finished on the server — open Build History to download the JAR."

Read that literally. The red panel means we lost track of your build, not that your code failed to compile. In almost every case the build finished on the server while your browser was cut off, and the result is sitting in Build History waiting for you.

A build that times out with no connection trouble says something different — "Build timed out after 5 minutes" — and that one makes no promise about a .jar.

Getting your .jar

  1. Open “Build & Export” in the Code Studio toolbar
  2. Pick History
  3. Open the newest build in the list — it shows whether it succeeded, how long it took and how big the .jar is
  4. Press Download JAR

If the file is not there yet

Two writers finish a build between them, so once in a while the build is marked done a moment before its .jar link lands. The app keeps quietly checking for about three minutes and pops up "Your JAR is ready to download." the moment the link appears.

If you have waited past that and History still offers no download, press Build again. Nothing is lost by doing so.

Rebuilding is free — Auto-Fix is not

Compiling your project costs no credits, however many times you press the button. A connection that dropped has not cost you anything, and pressing Build again to be sure is free.

Auto-Fix is different. It is a full AI run — it reads your files and the compiler output and writes corrected code — and it is billed like any other run. Do not press it because a build went red from a lost connection: there may be nothing wrong with your code at all. Look in Build History first, and only reach for Auto-Fix when the build itself really did fail with compiler errors.

Builds in the recent list do not stay downloadable forever. If the .jar you just rescued is one you are shipping, star it on your project's public page so it is kept as a permanent favorite — Build History explains how.

Where to next

14 of 22 in Minecraft Studio · Last checked 17 September 2026 · Previous: Cloud Build