Deploy fails: registry fdaa::3:5000 connection refused (LHR region)

[jakeyboy]

All deploys to our LHR-region apps have been failing for ~2 hours. Builds complete successfully but the push to the internal registry fails every time:

Error: failed to push registry.fly.io/retentionlab-api: dial tcp [fdaa::3]:5000: connect: connection refused

• Region: LHR
• Started: ~14:30 UTC, 26 March 2026
• Attempts: 10+ deploys, tried --remote-only, local Docker build, --depot=false, destroyed and recreated builder — all fail at the same registry push step
• Status page shows “All Systems Operational” but registry node fdaa::3 is clearly down

Last successful deploys were yesterday (25 March). Existing apps are running fine — just can’t push new images.

[mayailurus]

Hm… Another thing that could be tried is to move the builder over to a different region, like ams or cdg:

https://community.fly.io/t/region-cannot-host-your-machine-fra/23071/31

(These days, you might also need --recreate-builder, on that command line.)

[jakeyboy]

Thank you.

Tried the suggestions — --recreate-builder and --depot=false. The deploy cycled through 3 different builders (fly-builder-old-violet-4905, fly-builder-lingering-cloud-2611,
fly-builder-wispy-forest-8680). Two hit the original fdaa::3:5000 connection refused, one got an HTTP 500 (unable to upgrade to h2c, received 500).

[mayailurus]

What was the exact command line you were using?

(I just tried a build in iad and didn’t encounter any problems.)

[jakeyboy]

The deploy commands I was running:

Backend API:

cd backend && flyctl deploy --app retentionlab-api --remote-only

Celery Worker:

cd backend && flyctl deploy --config fly.worker.toml --app retentionlab-worker --remote-only

Frontend:

cd frontend && flyctl deploy --app retentionlab-app --remote-only --build-arg VITE_API_URL=https://retentionlab-api.fly.dev/api/v1

All three hit the same error — the Docker image builds and all layers push successfully, but the final registry push fails with:

ERROR: failed to push registry.fly.io/retentionlab-<app>:deployment-<id>: 
failed to do request: Head "https://_api.internal:5000/v2/retentionlab-<app>/blobs/sha256:<hash>?ns=registry.fly.io": 
dial tcp [fdaa::3]:5000: connect: connection refused

The builds are using Depot (Fly’s remote builder). The registry at _api.internal:5000 is refusing connections.

All three retries have now failed with the identical _api.internal:5000: connection refused error.

[roadmr]

hi @jakeyboy , can you try now? I moved your builder to a different region. (btw your Depot builder was in iad, not lhr)

[jakeyboy]

thanks so much! Backend is live, so moving to the rest. Cheers!

[alow]

I have been having the same issue with multiple apps, all with primary region IAD. First failure noticed around 16:30 UTC, deploys still failing now.