From FamilySearch Wiki

The database did not find the text of a page that it should have found, named "Austria, Vienna, Jewish Registers of Births, Marriages, and Deaths (FamilySearch Historical Records)/Known Issues" (Diff: 1218729, 1305360).

This is usually caused by following an outdated diff or history link to a page that has been deleted.

If this is not the case, you may have found a bug in the software. Please report this to an administrator, making note of the URL.