“KICKED: no valid heartbeat within window.”

A kick, not a launch failure

Every other string in this section stops you getting in. This one throws you out of a match you are already playing. The earliest public report located is a Report a Problem thread opened at 05:43 UTC on 20 September 2026 and titled with the message itself: “Game runs perfectly however, I keep getting “KICKED: no valid heartbeat within window”.” The player guessed at the anti-cheat. Five hours later a second thread, also titled with the message, described being kicked on an SA official server while waiting out lag so heavy they could not walk, with the red packet-loss icon showing. Two dated reports on one day, from two different situations, is what establishes the string. It establishes nothing about the cause.

Team17's one suggested step: check Elytra's certificate

Six minutes after the first report, Team17_Help — an account Steam flags [developer] — replied with a single procedure. It is a check on the digital signature of the anti-cheat's installer, which ships in the game's Elytra subfolder, and it ends with waiting until Windows reports the certificate as OK. The reply does not say what the certificate has to do with the kick, and it is a support suggestion to one player rather than a diagnosis. Two days later another player reported that it half worked: “it allows me to join games now but then kicks me between 20 seconds to a minute for no vaild heartbeat.” Team17_Assist [developer] asked them for any error messages. No further answer had been posted when this page was written.

On Linux, Team17's answer is that it is not supported

The same thread filled with players on Linux: one on Bazzite with Proton Experimental, another pointing out that there is no Digital Signatures tab to click on Linux. At 21:00 UTC Team17_Service [developer] answered both: “Currently WARDOGS it's not supported for Linux, we can't provide any recommendations at the moment.” That matches Team17's answer on the “Missing game executable” page and Valve's Unsupported rating for Steam Deck. A player in the thread goes further and says the heartbeat relies on a kernel-level feature Linux does not have. That is a player's explanation, and nothing official confirms or denies it.

Team17's other Linux answer, and the Deck rating →

When the network is already failing

The second report is a different situation: an SA official server so laggy that “everyone” was complaining, with the red packet-loss indicator on screen, and the kick arriving while the player sat in cover. The only reply is another player's guess that the server sent a check and heard nothing back. That fits the words of the message, but it is a guess. If you see the packet-loss icon before the kick, the network-symbol page explains what each colour has been reported to mean.

What the yellow, orange and red network icons mean →

Not the same as the heartbeat.dll crash, or the join timeout

Two neighbouring failures get confused with this one, and the difference decides which page helps you. If the game closes with no message at all a few seconds after you join, that is a crash of the Elytra anti-cheat service. Players have traced it in Windows Event Viewer to an illegal instruction inside a file called heartbeat.dll, on 19 and again on 20 September. If you never get into the match, or are dropped the moment you arrive with a timeout, that is 1628505091. The launch hotfix of 10 September named “unexpected kicks” among the problems it addressed, but printed no message, so nothing ties that notice to this string.

1628505091, the join timeout →

What is not established

Nobody at BULKHEAD or Team17 has said what the heartbeat is, how long the window is, or what makes one invalid. Nobody has said why an installer certificate check would affect it, or whether the one follow-up report that it only half worked is typical. Nobody has published how often it happens. There is also no published rule for kicks of any other kind: no AFK timeout, no vote kick, no team-kill kick. So a kick that shows a different message, or none, is not explained by this page. What you can do is narrow: Team17's certificate step on Windows, the network icon if lag came first, and the knowledge that on Linux there is no supported fix.

Common questions