You may encounter problems when connecting to a database or enterprise geodatabase from an ArcGIS Desktop client or when trying to register a database with an ArcGIS Server site. The following sections provide information on some common causes of connection problems.
Database client files are not present or are improperly configured
When you connect from a client application to a database or enterprise geodatabase, the database management system client files must be present on the connecting client computer. Each database has different requirements for setting up and configuring its client applications. See your database management system documentation to be sure you have properly installed and configured your database client on the ArcGIS client computer.
Note that when you upgrade your database, you should update the database client installations as well.
ArcGIS software includes PostgreSQL client files; therefore, you do not need to separately install and configure a PostgreSQL database client to connect to a PostgreSQL database or a geodatabase in PostgreSQL.
The database is not configured to accept connections
Databases may require additional configuration to allow remote clients to connect. For example, to connect to a PostgreSQL database, the database administrator must alter the pg_hba.conf file to allow clients to make a connection.
Microsoft SQL Server databases need network protocols set to accept connections over the network.
In many cases, the message you see in ArcGIS indicates you provided a bad login when connecting. If you are sure the user name and password you provided are correct, confirm the database can accept connections from remote clients.
See your database management system documentation to learn how to configure the database to accept client connections.
Connections have been blocked
There are several ways an administrator can prevent clients from connecting to a database. This is typically done to perform certain administration tasks, such as backups or upgrades, without anyone connected to the database.
The database administrator can block connections through functionality provided in the database management system. Most database management systems can be placed in a quiescent mode, which prevents new connections from being made to the database.
For enterprise geodatabases, the geodatabase administrator can block new geodatabase connections from the database connection in ArcGIS Desktop or using the AcceptConnections ArcPy function. When a client tries to connect to the geodatabase that is in this state, the following message is returned:
Failed to connect to database. The geodatabase is not accepting connections. Please contact your geodatabase administrator.
If you receive this message when attempting to connect to an enterprise geodatabase, contact your geodatabase administrator to determine if the block was intentional and, if so, when you can expect the geodatabase to be available again.
You're connecting to a database that ArcGIS considers to be a system database
Databases that are present when you install the database management system are considered by ArcGIS to be system databases. If you attempt to make a database connection to one of these databases, such as the master database in a SQL Server instance or the postgres or template1 database in PostgreSQL, you will receive the following message:
A database connection exception has occurred. Connections to system databases are not allowed. Please provide a different database for the connection.