Problem happened in 7.0-dev
line 35:
if response.error.error?
return alertService.add("danger", "Error: " + response.error.error, 6000)
potential fix, but should fix that in the API response instead.
if response?
return alertService.add("danger", "Error: " + response, 6000)
response expect an object but string are are used.

After the fix:
