Our CI builds universal test binaries using XCode 15 (on macOS 15), archives the results (together with Qt), and then deploys them to macOS 26.

After unpacking, most of the tests fail with the following error:

Server does not run

Basically, that means that the open62541-testserver binary is running, but the test is not able to connect to the server.

My investigation reveals that after unpacking the archive the first attempt to run a test always succeeds, so in principle the server is working. However, all subsequent attempts fail.

Starting the server manually reveals that it takes a long time (i.e. more than 10 seconds) before the server is ready to listen on a port.

The code in tests seems to be adapted to it:

QTest::qSleep(100);
socket.connectToHost(defaultHost, defaultPort);
if (!socket.waitForConnected(5000))
{
    bool success = false;
    for (int i = 0; i < 50; ++i) {
        QTest::qSleep(100);
        socket.connectToHost(defaultHost, defaultPort);
        if (socket.waitForConnected(5000)) {
            success = true;
            break;
        }
    }

    if (!success)
        QFAIL("Server does not run");
}

However, in practice I see that all socket.waitForConnected() calls return immediately.

Building Qt and tests directly on macOS 26 using XCode 26 works fine.