Open Dental Cannot Connect to the Server? NYC Fixes

The message is almost always the same: "Unable to connect to any of the specified MySQL hosts", shown after OK is clicked in the Choose Database window. The vendor's own troubleshooting page lists what to check when that appears, and every item on the list is a server, network or Windows item, not a program item. This page is what it means in a New York City office and what is fixed over a remote session.

Last updated: October 2026

What is the workstation actually trying to reach?

Four settings: the server's computer name, the database name (usually opendental), a MySQL user and its password. They live in the Choose Database window on each workstation, which appears on its own when the program cannot connect; a workstation set to use a Middle Tier holds a URI and an Open Dental user there instead. A typo in the server name after a re-image looks exactly like a dead server, so this window is read first.

The database runs as the MySQL service on one computer, and its data files must sit on that computer, not on a NAS. So "the server" means one box in the closet: is it on, is the service running, and can the operatory reach it on port 3306.

One workstation, or all of them?

All of them at once

The server is the suspect: off after a building power event, rebooted for a Windows update without the service restarting, or running with a database folder that went read-only or moved. The vendor's steps: start the MySQL service; if it will not start, suspect an antivirus or backup program; check the opendental data folder is in place with its roughly 1,200 files; clear a read-only flag if the window says the database is present but not accepting commands.

One machine only

The server is fine and something between that machine and it is not. The vendor names the firewall first: incoming traffic on port 3306 must be allowed on the server, including any firewall inside an antivirus product. Then the network (a machine no longer in the same workgroup or domain), then the credentials if MySQL users were set by hand. In a multi-tenant Manhattan building a third cause is common: a workstation that joined the guest Wi-Fi after a cable came loose.

Only the remote workers

That is the VPN, the remote gateway or the Middle Tier, not MySQL, and it belongs on the remote access page. The vendor opens port 3306 on the server, not on each workstation; exposing it to the internet to make a home connection work trades a connection problem for a security one.

Why does a dead connection matter more here?

New York requires prescriptions to be issued electronically, and a prescription written on paper during a temporary technological or electrical failure has to be noted in the patient's record. An afternoon with no database is an afternoon of documented exceptions. The state's data-security law also expects a business holding New Yorkers' private information to keep technical safeguards that detect, prevent and respond to attacks or system failures. A server that rebooted at 3 a.m. and never restarted its database service is exactly that; monitoring the service is part of this work.

What is done remotely?

1. Choose Database settings read on a failing workstation and a working one.
2. The server: power, Windows, the MySQL service, the data folder, in that order; the service started or the folder flag cleared as the vendor describes.
3. Port 3306 tested from the failing workstation; the Windows and antivirus firewall rules read on the server.
4. The workstation's network: right subnet, right domain, wired rather than guest Wi-Fi.
5. The vendor's services (OpenDentalService, eConnector) restarted if they stopped too.
6. Cause, fix and downtime written down for the practice's record.

A dead power supply, a dark switch or a cable pulled during a build-out next door is seen in that session, named, and handed to an electrician rather than the vendor.

Questions practices ask

Should I call the vendor first?

The vendor's page says it is best to contact them for this error. The checklist they give is server, firewall, network and service work, which is this side, and a practice with a current subscription can run both calls at once.

The database is there but the program says it will not accept commands

The read-only case: the data folder's read-only attribute is cleared for the folder, subfolders and files, then the program is started again, with a server restart if needed.

Is it time to move to a new server?

If the same box has done this twice, probably. The server migration page covers the move.

Could the cloud version avoid all of this?

It turns the connection problem into an internet problem; the cloud or server page weighs that.