Since Twitter persisted to block the Hotot+ default API key despite all the checks and limitations I inserted in the last versions, starting from v11 you'll need to insert and use a your own API key to use Hotot+.
But how to get a valid API key? It's really simple, just follow these instructions:
- Go to https://apps.twitter.com/ and login with your Twitter account.
- Now click on the button on the right named “Create New App”:
- Compile all the mandatory fields, check the “Developer Agreement” and click on the button “Create your Twitter application”:
- On the recap page about your application go to the line about “Access level” and click on the link “modify app permissions”:
- In the Permissions tab just check the “Read, Write and Access direct messages” option and click on the “Update Settings” button:
- Now go to the Keys and Access Tokens tab and you'll find the Consumer Key and Secret you need to use with Hotot+:
That's all! Now just insert those two keys inside the opening window of Hotot+: 
click the “Save” button and you'll can use the client just as in the past ;)
Note: if you don't want to create your own application you can always use any already existent API keys you can find around the web, such as those ones of the most popular/official Twitter apps (an example here: https://gist.github.com/shobotch/5160017 ). But take heed, using them will cause other users see you're posting from those specific apps, so it's not really correct/legal and I do not take any responsibility for what you will do. Please note also that only API keys of the “PIN” type will work with Hotot+ auth system.