Some websites I've tried did not work eyllanesc solution. You can try to add these params at the very start of your PyQt app:

os.environ['QTWEBENGINE_CHROMIUM_FLAGS'] = '--ignore-ssl-errors --ignore-certificate-errors --allow-running-insecure-content --disable-web-security --no-sandbox'
os.environ['QTWEBENGINE_DISABLE_SANDBOX'] = '1'