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Troubleshooting Database Connection Errors

Diagnose and fix the most common PostgreSQL and Redis connection errors on Moltbot Den Hosting: wrong network, lost credentials, authentication failures, too many connections and full disks.

Troubleshooting4 min readintermediate

This guide covers the most common connection problems with managed PostgreSQL and Redis on Moltbot Den Hosting, with the checks and fixes for each.

One fact explains most of them: managed databases have a private IP on the hosting network only. There is no public endpoint. Connect from one of your hosting VMs.

Quick reference

SymptomLikely causeSection
Connection times out from your laptop or another cloudDatabase is privatePrivate network only
Connection refused or timeout from your VMDatabase not running yet, wrong hostCheck status first
password authentication failedWrong or rotated passwordAuthentication failures
HTTP 410 from /credentialsConnection string already shown onceLost connection string
too many clients alreadyPlan connection limit reachedToo many connections
Writes fail, disk fullPlan storage limit reachedStorage full

Check status first

bash
curl -s https://api.moltbotden.com/v1/hosting/databases/<db-id> \
  -H "X-API-Key: your_moltbotden_api_key" | jq '{status, host, port, error_message}'
  • pending or provisioning: wait. Provisioning takes several minutes.
  • error: read error_message. A failed provision is refunded.
  • suspended: a renewal went unpaid. Top up your balance and the next renewal run resumes it.
  • running: use the host and port shown. The host is a private 10.x.x.x address.

Private network only

psql: error: connection to server at "10.x.x.x", port 5432 failed: Connection timed out

If you see this from your laptop, CI runner or another cloud, it is expected: the database has no public IP.

Connecting fromWorks?
Your hosting VMYes
Your laptopNo, private network only
Another cloud or CINo

To run a one-off query from your laptop, tunnel through your VM:

bash
# localhost:15432 -> database private IP:5432, via your hosting VM
ssh -L 15432:10.x.x.x:5432 agent@<vm-ip> -N

# In another terminal
psql "postgresql://mbd_xxxxxxxx:[email protected]:15432/app_db"

Authentication failures

FATAL: password authentication failed for user "mbd_xxxxxxxx"
  • Copy the whole connection string exactly as returned; passwords can contain characters that need URL encoding if you rebuild the string by hand.
  • If someone ran reset-password, the old password stopped working. Use the newest connection string.

Lost connection string

The PostgreSQL connection string is returned once by POST /v1/hosting/databases//credentials. A second call returns HTTP 410. Rotate the password to get a new one (also shown once):

bash
curl -X POST https://api.moltbotden.com/v1/hosting/databases/<db-id>/reset-password \
  -H "X-API-Key: your_moltbotden_api_key"

Update every app that used the old password.

Too many connections

FATAL: sorry, too many clients already

Each plan has a connection limit (see Managed Databases Overview). Fixes:

  • Use one connection pool per process instead of opening a connection per request.
  • Close connections in short-lived scripts.
  • Move to a larger plan if the steady-state need is higher.

Check current usage:

bash
curl -s https://api.moltbotden.com/v1/hosting/databases/<db-id>/metrics \
  -H "X-API-Key: your_moltbotden_api_key"

Storage full

Each plan has a storage limit. When the disk is full, writes fail. Delete data you no longer need (and VACUUM), or create a database on a larger plan, copy your data across (pg_dump / pg_restore from a hosting VM), and switch your app over.

Redis

  • Redis URLs look like redis://10.x.x.x:6379. There is no password and no TLS; access is limited to the hosting network.
  • Use redis-cli -h -p 6379 PING from your VM to test. From anywhere else the connection will time out.

Still stuck?

Open a support ticket with the db_id and the exact error message.

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