You submit a generation, the progress shows 0%, and 30 minutes later it’s still 0%. Or it sits at 5% — or, on Kling, the classic 99% — and never finishes. The platform doesn’t error out. It just hangs while you burn the time you set aside for the work.
Fastest fix first: hard-refresh the page (Cmd+Shift+R / Ctrl+Shift+R). A surprising share of “stuck” jobs already finished server-side and only the live progress bar disconnected. If a real refresh still shows it queued or stuck after roughly 30 minutes of no movement, cancel it, free your concurrency slot, and resubmit off-peak. The rest of this page is how to tell which of those you’re in.
Most AI video platforms (Runway, Pika, Kling, Luma, Hailuo) run a shared queue across all users, and paid tiers get queue priority. During peak hours a free-tier job can wait 30+ minutes — on Kling’s free plan, occasionally hours (as of June 2026). That’s normal queueing. A job that has been “running” with zero movement for over an hour is something else, and waiting won’t fix it.
Which bucket are you in?
| Symptom | Most likely cause | Go to |
|---|---|---|
| Progress bar frozen, no error | Frontend/websocket disconnect; job may be done | Step 1 (refresh) |
| Stuck at 99% (Kling especially) | Render finished, UI didn’t update | Step 1 (refresh) |
| “Queued”, peak hour, free tier | Normal peak queueing | Step 3 (off-peak) |
| Several jobs “running”, new one won’t start | Concurrency cap saturated | Step 2 (free a slot) |
| One old job “running” >1 hr, no progress | Prior job hung, still holding your slot | Step 2 (cancel it) |
| Everyone’s jobs failing right now | Platform-wide incident | Step 4 (status page) |
| Job never starts, others do | Request exceeds your tier limits | Step 5 (check limits) |
Common causes
Ordered by hit rate, highest first.
1. Frontend froze — the job actually finished or is still running
Your browser tab slept, the websocket dropped, and the progress bar stopped updating even though the render kept going (or completed) on the server. This is the single most common “stuck” report, and on Kling it shows up as the infamous stuck at 99%: the video is done, the UI just never flipped it to complete.
How to spot it: hard-reload the page or reopen the project/history view. The job often shows as completed, or jumps to its true progress.
2. Free-tier peak-hour queueing
US daytime and EU evening are peak. Free and lowest-priority queues sit behind every paid job. As of June 2026, free-tier benchmarks show 30+ minute waits at peak on Kling, and the free plan can stretch to hours when something is trending.
How to spot it: it’s a peak hour in major markets, you’re on free tier, and the status reads “queued” (not “processing”). The bar isn’t frozen — it just hasn’t reached you yet.
3. Account concurrency cap saturated
Most plans cap concurrent jobs, and higher tiers raise the cap. Runway retired Unlimited and replaced it with Max for new subscribers on June 1, 2026 (existing Unlimited subscribers auto-switch to Max on September 1, 2026); its newer credit-based plans run generations on demand with no fixed limit on how many you can queue at once, while older fixed-slot tiers cap concurrency lower. If you already have your cap running, the next one queues until a slot frees.
How to spot it: open the dashboard. You have several jobs in “running” state and the new one won’t start.
4. A previous job hung server-side and never released its slot
A render genuinely stalls (e.g., stuck at 50% for an hour), but the platform still counts it against your concurrency. Every new job queues behind a zombie.
How to spot it: a prior job has been “running” for over an hour with no progress change on refresh.
5. Platform-wide incident
Backend bottleneck or outage. Free and paid jobs alike stall.
How to spot it: check the platform’s status page (below), then X/Twitter or the official Discord. If others are reporting it in the last hour, it’s not your account.
6. Request exceeds your tier limits (silent reject)
You asked for 10s but your tier caps at 5s, or a resolution/mode your plan doesn’t include. Some platforms queue it indefinitely instead of returning a clear error.
How to spot it: your clip’s duration, resolution, or mode is above what your plan documents. Other, smaller jobs from the same account process fine.
Shortest path to fix
Step 1: Hard-refresh — confirm it isn’t already done
1. Hard refresh: Cmd+Shift+R (macOS) / Ctrl+Shift+R (Windows)
2. Reopen the project / "My Generations" / history view
3. Check whether the job is actually complete or shows its real progress
4. Still genuinely queued or frozen after ~30 min of no movement? Go to Step 2On Kling, this alone clears most “stuck at 99%” reports: the render had finished and only the front end lagged. If a refresh genuinely shows it still failing at 99%, the job is usually a heavy image-to-video render the model couldn’t finalize. Add a clear end frame, simplify the prompt, or switch to text-to-video (which Kling processes more reliably than image-to-video) and resubmit off-peak.
Step 2: Free your concurrency slot — cancel truly-hung jobs
If a job has been “running” for over an hour with no progress, it’s almost certainly a zombie holding your slot. Cancel it so new jobs can start.
# Cancel paths (as of June 2026)
- Runway: Dashboard -> open the asset/session -> Cancel
- Pika: My Generations -> open the job -> Cancel (or via Discord generation)
- Kling: AI Video -> My Tasks -> Cancel
- Luma: Dashboard / Library -> job menu -> CancelImportant on refunds: do not assume cancellation refunds credits. Kling does not reliably refund credits for failed or stuck generations — its main refund path is a short window (about 7 days) for new subscribers who’ve barely used their credits, and top-up credit packs are non-refundable (as of June 2026). Runway and Luma generally don’t deduct credits for a generation that never produced output, but confirm against your billing/usage page rather than the spinner.
Step 3: Submit at off-peak UTC hours
Peak / off-peak guide:
# Peak (expect the longest free-tier queues)
- US daytime: 14:00-22:00 UTC
- EU evening: 18:00-22:00 UTC
- Asia evening: 12:00-15:00 UTC
# Off-peak (shortest queues)
- 02:00-08:00 UTC (late night in the US, morning in Asia)
- Weekend mornings UTC are often lighterPaid tiers with queue priority feel this far less; if you live in a peak market and need fast turnaround, priority is what you’re actually paying for.
Step 4: Rule out a platform-wide incident
# Official status / outage channels (as of June 2026)
- Runway: status.runway.team (the older status.runwayml.com address now redirects here)
- Luma: status.lumalabs.ai
- Pika: official Discord (no formal status page)
- Kling: X/Twitter @Kling_ai + community Discord
# Also check
- X/Twitter search: "<tool name> down"
- Reddit r/aivideo for current outage threadsIf the status page is green but everyone’s posting failures, trust the crowd — status pages lag real incidents.
Step 5: Verify your job fits your tier limits
# Check before resubmitting
- Duration: within your plan's max (e.g., Pika 2.2 = 5s or 10s; Pikaframes up to 25s)
- Resolution: 720p / 1080p supported on your tier?
- Mode: free tier may exclude "pro"/"premium" or the newest model
- Features: extend, image-to-video, keyframes may be tier-gatedIf a smaller job from the same account succeeds while the big one hangs forever, you’ve found a silent tier reject. Trim duration/resolution and resubmit.
Step 6: Fall back to a lighter platform (or upgrade)
# Quick fallback (route the same shot elsewhere)
- Runway stuck -> try Kling or Pika
- Kling stuck -> try Hailuo (MiniMax): its free tier was the fastest in 2026 testing,
typically finishing in ~60-90s (5s clips, ~10 free gens/day)
- All stuck -> a multi-model router (e.g., WaveSpeedAI) can fan one prompt out
to Kling / Hailuo / Veo / Sora and take whichever clears first
# Long-term
- Paid tiers on most platforms run ~$20-100/mo and buy concurrency + queue priority
- Runway replaced Unlimited with "Max" for new subscribers on June 1, 2026
(existing Unlimited subscribers auto-switch on September 1, 2026)How to confirm it’s fixed
- The job moves off 0%/99% and reaches “completed” with a downloadable asset.
- Your dashboard shows fewer than your tier’s concurrency cap running (no zombie holding a slot).
- A fresh small test job (e.g., 5s, 720p) starts processing within the expected window for your tier.
Prevention
- Submit during off-peak UTC hours whenever the deadline allows.
- Keep no more than 1-2 jobs queued at once; let a batch finish before sending the next.
- Hold accounts on two platforms so you always have a fallback when one queues up.
- For deadline work, generate the day before, not the morning of.
FAQ
Is 30 minutes at 0% normal, or is it stuck? On a free tier at peak it can be normal — Kling free-tier waits routinely cross 30 minutes as of June 2026. The tell is movement: a status that still reads “queued” is waiting in line; a progress bar frozen mid-render after a real refresh is stuck. Over an hour with zero change is stuck regardless of tier.
Why does Kling get stuck at 99%? Almost always the render finished and the front end didn’t update. Hard-refresh or reopen “My Tasks” and the clip is usually there. Genuine 99% failures (rarer) tend to be heavy image-to-video jobs during server overload, where the model can’t decide how to finalize the last frame. Add a clear end frame, simplify the motion, shorten the clip, or switch to text-to-video (which Kling renders more reliably than image-to-video) and retry off-peak.
Will I get my credits back if I cancel a stuck job? Not necessarily. Kling does not reliably refund credits for failed or stuck generations (its main refund path is a short window, about 7 days, for new subscribers who’ve barely used their credits; top-up packs are non-refundable). Runway and Luma usually don’t charge for a generation that produced no output, but verify on your usage/billing page, not the progress spinner.
Cancelling does nothing, new jobs still queue. Why? You’re likely still over your concurrency cap, or a zombie job is holding a slot. Refresh the dashboard, confirm how many jobs are actually “running”, and cancel the oldest hung one. New jobs can’t start until you’re back under the cap, and that cap is lower on entry tiers than on higher-volume plans.
Which platform has the shortest free queue right now? In 2026 testing, Hailuo (MiniMax) free tier was the fastest, typically finishing in ~60-90 seconds even at peak, with ~10 free generations a day (5-second clips on free). It’s the most reliable fallback when Runway, Pika, or Kling are backed up.