Complex sentence: Hitler almost certainly was enlisted by an error on behalf of the government, this is based on a report carried out by the Bavarian authorities in 1924 which questioned how Hitler was allowed to serve in the Bavarian Army.
Split into simpler sentences: Hitler almost certainly was enlisted by an error on behalf of the government. This based on a report by the Bavarian authorities in 1924 which questioned how Hitler was allowed to serve in the Bavarian Army.