Sorry there was a mistake in my original post. It seems that the connection to wordpress.com (NOT Woocommerce) cannot be established correctly.
The site with https://www.tnzr-clothing.de (NOT https) is listed as a blog at wordpress.com under my blogs. I have tried disconnecting or reconnecting with no success.
The console throws an error 500. Unable to insert blog. Please try again or contact support
I used the jetpack debuger to check the XML-RPC connection. Since the page is in a wp subfolder, I get the correct message for the URL https://tnzr-clothing.de/wp/xmlrpc.php “XML-RPC server accepts POST requests only.”
Screenshots: https://www.dropbox.com/scl/fo/w1z8rojvth9w5nhylqads/h?rlkey=h0apthzo2esidf8ivrlp0lqy4&dl=0
Maybe it will help to disconnect the old http site? Can you help me with this problem. Many thanks for your help.