Error 401 when sending a message but I'm already logged in

Hi, I have a XMPP server in my house and I was testing it in android using smack and yesterday everything was working but now every time I send a message it responds saying

<message to="raspserver/7ja58v1zem" id="0KtQg-58" type="error">
	<body>j</body><error code="401" type="auth"><not-authorized xmlns="urn:ietf:params:xml:ns:xmpp-stanzas"/></error>
</message>

But the user is already signed in.

There is a similar post but it doesn’t have any answer so I want to see if I’m lucky.