Letsencrypt problems with install

We installed two different new UCS-Server (v 4.4.8), in different networks, and after the configuration we wanted to install Letsencrypt to create some certs for the OX-Webmail-Interface.
But as soon as we install the app and configure in the Webinterface the domain-name and that we wont to configure it for “Apache2”, the following error accured:

  • Apach2 can’t start again
    ‘SSLCertificateFile: file "/etc/univention/letsencrypt/signed_chain.crt’ does not exist or is empty’

  • Error while install letsencrypt:

Traceback (most recent call last):
  File "/usr/share/univention-letsencrypt/acme_tiny.py", line 197, in <module>
  File "/usr/share/univention-letsencrypt/acme_tiny.py", line 193, in main
    signed_crt = get_crt(args.account_key, args.csr, args.acme_dir, log=LOGGER, CA=args.ca, disable_check=args.disable_check, directory_url=args.directory_url, contact=args.contact)
  File "/usr/share/univention-letsencrypt/acme_tiny.py", line 125, in get_crt
    authorization, _, _ = _do_request(auth_url, err_msg="Error getting challenges")
  File "/usr/share/univention-letsencrypt/acme_tiny.py", line 45, in _do_request
    raise ValueError("{0}:\nUrl: {1}\nData: {2}\nResponse Code: {3}\nResponse: {4}".format(err_msg, url, data, code, resp_data))
ValueError: Error getting challenges:
Url: https://acme-staging-v02.api.letsencrypt.org/acme/authz-v3/88687574
Data: None
Response Code: 405
Response: {
  "type": "urn:ietf:params:acme:error:malformed",
  "detail": "Method not allowed",
  "status": 405

Does this crt doesn’t autogenerate?
Any ideas?

Thank you!