QCA Report “Failed to load Legacy provider”

Question

windows 10 install：

vs2019

Win64OpenSSL-3_0_5

qca-2.3.4

qt-5.15.2

using cmake build and install to qt directory

then I test the library.

bool temp = QCA::isSupported("cert", QStringLiteral("qca-ossl"));

the program exit here,and report “Failed to load Legacy provider”

note，this code used by qgis.

the program load dll correctly！

QCA::Initializer init;

QCoreApplication app(argc, argv);

QCA::scanForPlugins();

bool temp4s = QCA::isSupported("sha224", QStringLiteral("qca-ossl"));