send email

In your process model you are calling your Integration with a 'Call Integration' Smart Service. In the Data Outputs of this node you will be able to see a' Success' attribute. You can pass this value into a process variable, and, if this is set to false(), you can then handle the integration failure. Note that at this point you'll probably want to build your own way of managing errors - so maybe a sub-process that assigns a Task to the Administrators Group (this will then send an email which Users in the Administrators Group will receive) You'll probably want to make this sub-process as generic as possible so it can be re-used throughout your Application or (depending on the scope of responsibility for the Administrators) across many Applications. You'll also want to consider what sort of experience you want the end User to have, depending on whether a User is synchronously waiting for a result that includes a call to this Integration.

is there any shorter way ?

I think you're missing the point. Sending the email is ONLY the way to notify someone that something has happened. You need to MANAGE what has happened. Emails get lost. Appian Tasks do not. An email only gets sent to the Administrator if that's who you configure it. What about the poor end-user who is wondering what on earth has happened to their latest interaction with the system? (if the Integration is in a synchronous process). And how can you put the End User in contact with the Administrator so they both know they're talking about the same error? A holistic solution needs to address these questions and not just think about the happy path or the immediate issue to hand.

I think you're missing the point. Sending the email is ONLY the way to notify someone that something has happened. You need to MANAGE what has happened. Emails get lost. Appian Tasks do not. An email only gets sent to the Administrator if that's who you configure it. What about the poor end-user who is wondering what on earth has happened to their latest interaction with the system? (if the Integration is in a synchronous process). And how can you put the End User in contact with the Administrator so they both know they're talking about the same error? A holistic solution needs to address these questions and not just think about the happy path or the immediate issue to hand.