When it tries to embed the destination page in the iframe, there is a redirection error. However, this redirection is also in normal installations but there it is not causing error.
I suspect that what might be happening is that your app is still using the legacy authorization code grant flow logic, which tries to redirect to /admin/oauth/authorize when it doesn’t have a valid access token. With managed installations, this redirect attempt happens inside the iframe, which browsers block for security reasons.