IP ban normally is a result of multiple requests from the same IP. How many accounts are being used in your household using the same IP at the same time? This could trigger a soft IP ban too.
Looking at your log, I'm suspecting that you received a soft ban which prevented you from looting the pokestop. But your soft IP ban may be a result of repeated and multiple failed request in short period of time, 28 times altogether, and may have been interpreted by Niantic as DDoS attack on their server. Pokefarmer has no built-in protection on "failed to loot" softban. It will allow you to perform almost endless unsuccessful loot depending on your setting. The built-in protection that is has is on "pokemon fled" softban, which will cause PF to stop and give you the "Restricted blah blah" warning. If PF did not include that protection, the bot may just walk around all night, trying to "unsuccessfully" catch pokemon all night, until it triggers an IP ban too.