Example to reproduce:
When visiting https://de.wikipedia.org/wiki/Benutzer:CTHOE/Fototouren with the Android App and then clicking the first link Rothenbach in the first table the preview window opens saying: "An error occurred". However, when clicking the title of the preview window the article is opened correctly.
This holds for several but not all linked articles in this list. On the first glance i could not find out what the difference between these articles is.
Expected behavior: I would expect that if the article exists also the preview can be generated.
The following request appears to provide an empty text extract: