[satosa-users] skipped backend attribute ['email', 'emailAddress', 'mail']: no value found

Hello, I am deploying SaToSa version 8. But, it seems that the backend module is failing to map attribute from the IdP to internal proxy attributes. In fact, after the user's is authenticated, and accepted the consent, i got : KeyError 'mail' in the satosa log. What should i have missed in the configs ? Below is part of the log 2022-09-09 20:04:11,840] [DEBUG] [satosa.attribute_mapping.to_internal] skipped backend attribute ['email', 'emailAddress', 'mail']: no value found satosa-proxy_1 | [2022-09-09 20:04:11,840] [DEBUG] [satosa.attribute_mapping.to_internal] skipped backend attribute ['cn']: no value found satosa-proxy_1 | [2022-09-09 20:04:11,841] [DEBUG] [satosa.attribute_mapping.to_internal] skipped backend attribute ['sn', 'surname']: no value found satosa-proxy_1 | [2022-09-09 20:04:11,841] [DEBUG] [satosa.attribute_mapping.to_internal] skipped backend attribute ['eduPersonScopedAffiliation']: no value found satosa-proxy_1 | [2022-09-09 20:04:11,841] [DEBUG] [satosa.attribute_mapping.to_internal] skipped backend attribute ['eduPersonPrincipalName']: no value found satosa-proxy_1 | [2022-09-09 20:04:11,842] [DEBUG] [satosa.backends.saml2._translate_response] [urn:uuid:722089a1-b43e-47b0-bd98-2888c96b3a10] backend received attributes: satosa-proxy_1 | {} satosa-proxy_1 | [2022-09-09 20:04:11,842] [ERROR] [satosa.base.run] [urn:uuid:722089a1-b43e-47b0-bd98-2888c96b3a10] Uncaught exception satosa-proxy_1 | Traceback (most recent call last): satosa-proxy_1 | File "/src/satosa/src/satosa/base.py", line 240, in run satosa-proxy_1 | resp = self._run_bound_endpoint(context, spec) satosa-proxy_1 | File "/src/satosa/src/satosa/base.py", line 180, in _run_bound_endpoint satosa-proxy_1 | return spec(context) satosa-proxy_1 | File "/src/satosa/src/satosa/backends/saml2.py", line 363, in authn_response satosa-proxy_1 | return self.auth_callback_func(context, self._translate_response(authn_response, context.state)) satosa-proxy_1 | File "/src/satosa/src/satosa/base.py", line 141, in _auth_resp_callback_func satosa-proxy_1 | subject_id = [ satosa-proxy_1 | File "/src/satosa/src/satosa/base.py", line 142, in <listcomp> satosa-proxy_1 | "".join(internal_response.attributes[attr]) for attr in satosa-proxy_1 | KeyError: 'mail' satosa-proxy_1 | [2022-09-09 20:04:11,843] [ERROR] [satosa.proxy_server.__call__] Unknown error satosa-proxy_1 | Traceback (most recent call last): satosa-proxy_1 | File "/src/satosa/src/satosa/base.py", line 240, in run satosa-proxy_1 | resp = self._run_bound_endpoint(context, spec) satosa-proxy_1 | File "/src/satosa/src/satosa/base.py", line 180, in _run_bound_endpoint satosa-proxy_1 | return spec(context) satosa-proxy_1 | File "/src/satosa/src/satosa/backends/saml2.py", line 363, in authn_response satosa-proxy_1 | return self.auth_callback_func(context, self._translate_response(authn_response, context.state)) satosa-proxy_1 | File "/src/satosa/src/satosa/base.py", line 141, in _auth_resp_callback_func satosa-proxy_1 | subject_id = [ satosa-proxy_1 | File "/src/satosa/src/satosa/base.py", line 142, in <listcomp> satosa-proxy_1 | "".join(internal_response.attributes[attr]) for attr in satosa-proxy_1 | KeyError: 'mail' satosa-proxy_1 | satosa-proxy_1 | The above exception was the direct cause of the following exception: satosa-proxy_1 | satosa-proxy_1 | Traceback (most recent call last): satosa-proxy_1 | File "/src/satosa/src/satosa/proxy_server.py", line 148, in __call__ satosa-proxy_1 | resp = self.run(context) satosa-proxy_1 | File "/src/satosa/src/satosa/base.py", line 258, in run satosa-proxy_1 | raise SATOSAUnknownError("Unknown error") from err satosa-proxy_1 | satosa.exception.SATOSAUnknownError: Unknown error