Closing this ticket since the last investigations proved that the errors linked to this ticket were either fixed in the new help center or are an actual lack of permissions.

I investigated the errors reported on this ticket and pretty much all of them were already fixed when the new help center experience was released.

I've also checked https://getsupport.atlassian.com/browse/PSCLOUD-47123 and noticed that the 403 error happens when calling `/servicedesk/customershim/secure/attachment`
The only way that this URL is can be called is through the links in the email notification.
I managed to reproduce the error by logging into the help center with a user that has access to the help center but not access to the issue.

There are a two possibilities that can make this happen:
1 - The user that follows the link is logged in with a different account from the one that created the task.
2 - The user that follows the link used to be one of the participants in the request but was removed

So in this case, I don't believe this is actually an error but a real lack of permissions.

cc d4f60db6c681

While creating the ticket, im unable to attached the files and getting an error called unknown server 403,
please let me know what could be the reason and how to fix it,

Thanks and Regards
Santhosh kumar

Same issue is happening on the Data Centre Version.

One of our customers also reported this. Does anyone have a workaround for this?

For server instances there's another issue JSDSERVER-6082

The same after upgrade from 3.12 to 3.16 (we don't use cloud, we have server installed)

We have the same problem. The request type is correct and the customer is unable to view attachments unless linked. Note that we are on server and not cloud.

We use Jira Service Desk server and have the same problem. 

Same problem here! 

@admin174626559 in our case that reason doesn't aplly! Our issues have the correct request type.