Got it.
A trivial PHP script:
<?php
$servername ="localhost";
$username = "resourcespace";
$password = "[my pw]";
$conn = new mysqli($servername, $username, $password);
if ($conn->connect_error) {
die("Connection failed: " . $conn-connect_error);
}
echo "connected OK";
?>
returned the error message "The server requested authentication
method unknown to the client". After some research, I changed the
mysql authentication plugin:
mysql> ALTER USER 'resourcespace'@'%' IDENTIFIED
WITH mysql_native_password BY '[my pw]';
This allowed the little test script, and ResourceSpace, to connect
to the database.
It is possible to set the default authentication plugin to
"mysql_native_password" in the mysql configuration files, but I
haven't experimented with this.
It would have been helpful to have more complete information about
the error displayed on the "setup.php" page. Outlining the server
host name in red was not much use.
--- Peter Payzant