Hi,
When using provisioning with a https url allowing for optional client certificate auth, the http client will trigger belle_request_process_auth_requested which will cause the provisioning to fail.
In case of "http auth requested" (especially for optional SSL client auth), I believe linphone should try to continue with the request without auth rather than just failing the request. In the meantime we have setup a secondary URL that has no client certificate auth, but we usually run all our provisioning through the same place.
Alternatively, it'd be interesting to see linphone support client certificate authentication for provisioning.
Thanks,
M.