In this bug report titled “Error when deleting a topic which has already been answered,” Thomas_DC reports encountering an error message — An error occurred: There was an error deleting that topic. Please contact the site's administrator. — when attempting to delete a topic that has received replies. He notes inconsistent UI behavior: sometimes the delete button is hidden while edit remains visible; other times, the delete button appears but denies permission. Canapin asks for more context — user role, category permissions, console logs, and example topics — and mentions that automatic topics (e.g., “About this category”) can’t be deleted. Thomas provides a test link on try.discourse.org, but notes the instance resets daily, making reproduction difficult. Moin confirms that delete buttons remain visible for replied topics but display a permission warning on hover, and doesn’t recall seeing edit enabled while delete is hidden. Jagster points out that non-admin/moderator users have limited delete/restore rights. Canapin adds that by default, users can’t edit/delete posts after 24 hours (30 days for TL2). Thomas_DC questions why the system shows a generic error instead of a clear permission message. He also suggests resetting try.discourse.org weekly instead of daily to allow longer testing windows Thomas_DC. The issue remains partially unresolved, with no confirmed reproduction by staff, and hinges on user permissions and platform defaults.
Hi 
When I try to delete a topic which has already been answered, I get an error.
An error occurred: There was an error deleting that topic. Please contact the site's administrator..How is it handled?
I see that sometimes the delete button is hidden, whereas the edit button is available, and sometimes the delete button is available and tells me that I’m not allowed to delete the topic.
You can’t delete certain topics, those that are automatically created by Discourse, like the “About this category” topics.
I created a topic on my (up-to-date) instance, replied, and could delete the topic.
Can you give us examples of topics you can’t delete?
Are you admin or moderator?
What are the category permissions?
Did you try in safe mode?
Are there errors in the js console, or the network tab of your browser’s dev tools?
Are there errors in /logs?
Oh, so what’s different here?
https://try.discourse.org/t/test-for-deleting-a-topic-which-has-already-been-answered/1502
The delete button is hidden yet.
Should I do it again, or are you able to reproduce it there?
None.
I think: none. I don’t know what you call it.
You should see it if you succeed in reproduce it. Please tell me if you don’t.
I know that the delete button is visible even if the topic has a reply, so you aren’t allowed to delete the topic. The text on hover also reflects that. Example from the last topic I created at Meta:
But I don’t remember noticing a topic where the edit button was visible but the delete button was not.
That’s what I get here (for ex for this topic).
That’s what I get there, after a few time: https://try.discourse.org/t/test-for-deleting-a-topic-which-has-already-been-answered/1502
I don’t know how much time exactly, but it could be 1 hour, since I made https://try.discourse.org/t/test-for-deleting-a-topic-which-has-already-been-answered/1502 to be able to continue testing, after it happened to https://try.discourse.org/t/1st-test-for-deleting-a-topic-which-has-already-been-answered/1500.
I also don’t know whether the topic has to have already been answered or not for this to happen.
And I can’t test it yet: An error occurred: We appreciate your enthusiasm! That said, for the safety of our community, you’ve reached the maximum number of topics a new user can create on their first day. Please wait 20 hours and you’ll be able to create more new topics.
But then your rights to delete and restore are very limited 
By default, users can’t edit or delete their posts after 24 hours (30 days for trust level 2 users), which might explain why you can’t delete some of your posts.
Links to try.discourse.org quickly expire, as the instance is reset each day.
Well, why not tell “you aren’t allowed to delete the topic”, instead of showing an error?
Even if you can’t see my tests, did you try to reproduce what I told, and did you succeed or not?
BTW, why not reset try.discourse.org each week instead, so we’ll be able to test this kind of things?