Description
When fetching active users with the API some pages of `/admin/users/list/active.json` return a HTTP 500.
Workaround
If the problematic pages are skipped the other pages can be fetched without problem.
Error
The server error that caused the HTTP 500:
```ruby
NoMethodError: undefined method ‘[]’ for nil (NoMethodError)
main_user_record\[:silenced_till\]
^^^^^^^^^^^^^^^^
from app/models/user.rb:1335:in `silenced_till’
from active_record/attribute_methods/query.rb:48:in `public_send’
from active_record/attribute_methods/query.rb:48:in `query_attribute’
from active_model/attribute_methods.rb:273:in `silenced_till?’
from app/serializers/admin_user_list_serializer.rb:51:in `include_silenced_till?’
from active_model/serializer.rb:375:in `include?’
…
```
Our system logs indicate we started getting these errors after we upgraded from Discourse v3.5.1 to v3.5.2 in late October 2025. The referenced lines were introduced in FIX: Delegate silenced_till from anonymous user to main user account · Pull Request #32416 · discourse/discourse as discussed in Silenced user can circumvent it entering anonymous mode - #12 by pangbo .
Solution
I’m no Ruby expert myself, but since it looks to me that this happens with the API JSON pages that contain users that hasn’t been active since the changes in v3.5.2 I would guess there is a missing database migration handling some corner case with this change.