How to perform exception handling when any node withing the process fails or sus

@parvezs Here goes my suggestion to your question:
How to perform exception handling when any node withing the process fails or suspends?
To the best of my knowledge, there isn't a perfect solution that fits your usecase but I would like to suggest to refer the approach pointed by @siddharthg at https://forum.appian.com/suite/tempo/entry/e-155795. That's how I have done or seen so far but this may not fit all the scenarios. Let's see the other practitioner's suggestions.

basically I should be able to show an error screen to end user with some basic information.
It would be worth elaborating the above sentence. I guess, knowing about the error by checking the alert mails and thereby identifying and resolving the issue should be part of the users who support the application. As the chain breaks(if exists) when the node fails, out of interest, I would like to know how you want to surface the same to end user (i.e. a new user input task to user? or a status in dashboard? etc).

@sikhivahans I just want to let end user be informed that due to some system exception in the process they cannot proceed further and then provide them with admin contact information for further diagnosis. At this time I want to let them know which process id or task id failed.

@parvezs As discussed above you could refer https://forum.appian.com/suite/tempo/entry/e-155795 to obtain an idea of how it could be done. But this approach definitely won't work always, for example we used this kind of mechanism over the batch processes that were run by system in order to let everyone know if it's completed or struck with any problems before everyone starts working in the morning on the site.

I guess the best part would be leave it to the users who support the application. As soon as an alert is triggered, an email will be sent to targeted users, and the users who are responsible for sorting this can action the item immediately without waiting for any details from the end users.

we normally need exception handling mechanism on the integration points like web service integration. A call to web service may return fault or service timeout other then expected response.
In our project ,we have created a utility process which retry the web service node for three times with two minutes interval so if the 'call web service' does not return response within on min, we consider it as service timeout and trigger utility process.
If the service gets timeout again even after 3 retry calls then it creates task to administrator with process name , step name and service Request with an option to retry or ignore it . Based on the business logic then the Administrator can take action on it.

Thanks every one for comments. I think we should have such try catch exception handling OOTB in Appian.