diff --git a/base/univention-system-activation/src/wsgi.py b/base/univention-system-activation/src/wsgi.py
index 994adeafb7..8b47a8bd8b 100644
--- a/base/univention-system-activation/src/wsgi.py
+++ b/base/univention-system-activation/src/wsgi.py
@@ -70,6 +70,10 @@ def clean_license_output(out):
 
 
 def application(environ, start_response):
+
+	class LdapLicenceFetchError(Exception):
+		pass
+
 	def _error(message, trace=None):
 		return {
 			'status': 500,
@@ -92,13 +96,16 @@ def application(environ, start_response):
 
 	# output the license upon GET request
 	if environ.get('REQUEST_METHOD') == 'GET':
+		cmd = ['usr/bin/sudo', '/usr/bin/univention-ldapsearch', '-LLL', 'objectClass=univentionLicense']
+		proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
 		try:
-			out = subprocess.check_output(['/usr/bin/sudo', '/usr/bin/univention-ldapsearch', '-LLL', 'objectClass=univentionLicense'])
+			out, err = proc.communicate()
+			if proc.returncode:
+				raise LdapLicenceFetchError('cmd: {}\nreturn code: {}\nstdout: {}\nstderr: {}'.format(cmd, proc.returncode, out, err))
 			out = clean_license_output(out)
 			return _finish(data=out)
-		except subprocess.CalledProcessError as exc:
-			_log('Failed to read license data from LDAP:\n%s' % exc)
-			return _finish('500 Internal Server Error', _error('Failed to read license data from LDAP:\n%s' % exc))
+		except LdapLicenceFetchError as exc:
+			return _finish('500 Internal Server Error', data=_error('Could not fetch licence from ldap', traceback.format_exc()))
 		except Exception as exc:
 			return _finish('500 Internal Server Error', data=_error(str(exc), traceback.format_exc()))