Appian CMIS connector to Alfresco -scsExternalSystemKey setting

Question

Following https://docs.appian.com/suite/help/17.4/fnc_connector_cmi_a_cmigetrepoinfo.html 
 In expression rule, 
 =with( local!cmisResult: a!cmiGetRepoInfo( scsExternalSystemKey:"alfresco", usePerUserCredentials: true, atomPubUrl: " dxxx/.../atom", repositoryId: "d0c720ee-6349-4334-8763-8f0cc73dx" ), if(local!cmisResult.success, local!cmisResult.result, local!cmisResult.error ) ) 
 
 I have defined the third party credential as "alfresco", but still got this message: 
 Dictionary title: "Credential key not defined" message: "You do not have credentials configured for this system [key=alfresco]. Please navigate to the Third-Party Credentials page in your Settings and provide credentials for this system." detail: "You do not have credentials configured for this system [key=alfresco]. Please navigate to the Third-Party Credentials page in your Settings and provide credentials for this system." 
 
 I verified my user name, password, and atomPub with cmis workbench, which can connect alfresco. What is wrong with my setting to get the error: You do not have credentials configured for this system [key=alfresco] 
 Thanks in advanced.

Tristan Newmann · Accepted Answer

Hi Bill, 
 
The error message that you are seeing relates to the fact that it can't find the credentials with the key you specified, as opposed to an authentication/connectivity issue. 
 
I can see in your expression snippet that you are passing "true" for the input "usePerUserCredentials", but in the configuration for the credentials, you don't have the same option enabled. Do you intend to use per-user credentials for this integration? If so, you will need to enable this in your configurations and ensure that your personal Secure Credentials Store has the appropriate configurations. 
If not, you will need to set "userPerUserCredentials" false in your expression.

Josh · Answer

You are correct about the plugin list being blank - these are OOTB connectors so we should be good there. As a sanity check, you may want to copy the key "alfresco" from the admin console and paste it into your expression rule to make sure there isn't a weird formatting or case issue. 
 
Secondly, set usePerUseCredentials to "false" and uncheck the "allow users to specify their own credentials" to see if that helps any.