Error "Lost link to database" on login

Problem

After entering credentials on the login page, the error message "Lost link to database" appears. Login fails.

Cause

i-doit cannot establish a connection to the tenant database. Common causes:

• The database user does not exist (e.g. after a server migration)
• The stored database credentials are invalid
• The MariaDB/MySQL service is not reachable
• The database user does not have read permissions on the tenant database

Diagnosis

Test database connection

On the i-doit server command line, check whether the database user can log in:

mysql -h localhost -u idoit -p

If the login fails, the credentials are invalid.

Check database permissions

After successful login, test access to the tenant database:

USE idoit_data;
SHOW TABLES;

If error messages appear, read permissions are missing.

Check tenant configuration

The database credentials for each tenant are stored in the system database:

USE idoit_system;
SELECT isys_mandator__title, isys_mandator__db_host,
       isys_mandator__db_user, isys_mandator__db_pass
FROM isys_mandator;

Verify that the stored values are correct.

Solution

Create or correct database user

If the user is missing (e.g. after a server migration), it can be recreated:

CREATE USER 'idoit'@'localhost' IDENTIFIED BY 'secure_password';
GRANT ALL PRIVILEGES ON idoit_data.* TO 'idoit'@'localhost';
FLUSH PRIVILEGES;

Replace idoit, idoit_data, and the password with the actual values of your installation.

Update tenant credentials

If the credentials in the system database are no longer correct, they can be corrected in the Admin Center under Config — or directly in the database:

USE idoit_system;
UPDATE isys_mandator
SET isys_mandator__db_user = 'idoit',
    isys_mandator__db_pass = 'secure_password'
WHERE isys_mandator__title = 'Tenant';

Detailed documentation: Troubleshooting in the Knowledge Base