Partial Views API error

[PragmaticIT]

Which Umbraco version are you using?

15.3.0

Bug summary

I have Umbraco instance hosted behind the proxy.
Umbraco:CMS:WebRouting:UmbracoApplicationUrl in the appsettings.json file is pointing to the external URL.
When I open Umbraco by its external URL, navigate to Settings tab, then in the Templating section of the tree I select Partial Views a list of templates is displayed, however, whenever I click on any of them, broken Error page is displayed. The error has no translation (I have English as profile lang) and says

entityDetail_notFoundTitle
entityDetail_notFoundDescription

and the red toast is poping up saying just ApiError

When I try to create a new partial view template, the UI also reports an API error but reveals a little more details

saying partial-view not found (red toast appears, no details). The file is created in the filesystem, but Umbraco can not read it back.
No error is written in the log, no error description is shown in the API response.
When I do the same accessing Umbraco with machine URL, everything works perfectly fine.
The Host and X-Forwarded-Host headers are properly set by the proxy and the Hostname is set correctly based on their value.

Specifics

Steps to reproduce

1. install umbraco behind reverse-proxy
2. open Umbraco with external(proxy) URL
3. navigate to the Settings tab
4. scroll to the Templates
5. select Partial Views
6. select create
7. put file name and save
8. error appears

For error in partial view edit just follow the above and in step 6 select any existing template. Error appears.

Expected result / actual result

Umbraco should display the template content and let user to edit it - as it is when Umbraco is used locally.

[github-actions]

Hi there @PragmaticIT!

Firstly, a big thank you for raising this issue. Every piece of feedback we receive helps us to make Umbraco better.

We really appreciate your patience while we wait for our team to have a look at this but we wanted to let you know that we see this and share with you the plan for what comes next.

• We'll assess whether this issue relates to something that has already been fixed in a later version of the release that it has been raised for.
• If it's a bug, is it related to a release that we are actively supporting or is it related to a release that's in the end-of-life or security-only phase?
• We'll replicate the issue to ensure that the problem is as described.
• We'll decide whether the behavior is an issue or if the behavior is intended.

We wish we could work with everyone directly and assess your issue immediately but we're in the fortunate position of having lots of contributions to work with and only a few humans who are able to do it. We are making progress though and in the meantime, we will keep you in the loop and let you know when we have any questions.

Thanks, from your friendly Umbraco GitHub bot 🤖 🙂

[AndyButland]

Have you been able to replicate this locally @PragmaticIT? E.g. with a reverse proxy/local tunnel like beeceptor.com. I've been looking at that today to try to get that setup, so I can then debug and see what error you are getting. But I can't seem to get the backoffice login screen to load.

If you had any pointers on how to replicate locally that would be appreciated. Failing that, if you can dig out the details of the API error from the browser console or log file, that might help to to see what's going on.

[PragmaticIT]

Hopefully I'll have some more time during easter time and I'll try to replicate the issue in the isolated environment. I'll let you know about the progress