Troubleshooting

Collect logs

docker compose ps
docker compose logs --no-color > syntho.log

You can share syntho.log with Syntho Support at [e-mail].

Quick triage

1. Check container status: docker compose ps.
2. Check logs: docker compose logs -f.
3. Confirm host ports are reachable (or via reverse proxy).
4. Confirm .env matches your access method (HTTP vs HTTPS).

UI not reachable

• Check containers: docker compose ps.
• Check logs: docker compose logs -f.
• Confirm your reverse proxy / firewall exposes port 3000 (or your configured port).

Common causes

• Wrong FRONTEND_DOMAIN / FRONTEND_PORT in .env.
• Reverse proxy not forwarding websockets.
• TLS enabled at the proxy, but Syntho configured for http (cookie/security mismatch).

Image pull failures

Fix:

Use the registry host and credentials provided by Syntho to login with:

docker login syntho.azurecr.io -u <USERNAME> -p <PASSWORD>

Ensure that syntho.azurecr.io is added to your firewall allowlist to enable image pulls

Then:

docker compose pull
docker compose up -d

Login loop / can’t stay logged in

If TLS is terminated at a reverse proxy / load balancer / Ingress, Syntho must be configured for https.

If Syntho is configured for http, browsers can reject cookies.

Symptoms include login loops or sessions not sticking.

Fix:

• Set the frontend protocol to https.
• Disable secure cookies.

Backend / Core API errors (5xx)

Check which service errors:

docker compose logs -f backend
docker compose logs -f backend-worker
docker compose logs -f core-api
docker compose logs -f core-api-worker

If you use external PostgreSQL/Redis, verify network access from the host.

External PostgreSQL issues

Checks:

• Host can reach PostgreSQL (DNS, routing, firewall, security groups).
• User has permissions to create tables and run migrations.
• DB names match your .env.

If you use the bundled PostgreSQL from deployment-tools, the default database names are:

• syntho-backend (Backend)
• syntho-core (Core API)