If you’re getting an error when trying to log in to exhentai.org or ehentai.org, it may be attempting to validate the login attempt by captcha. HDoujin Downloader currently has no way of dealing with this captcha, so the login attempt fails. Worry not, because there’s still a solution.
First, log in normally through your browser. Once you’re logged in, open your browser’s cookie manager to view your login cookies. In Google Chrome, for example, this can be done by clicking the far left portion of the address bar, and clicking “Cookies”:
From there, you will see a list of domains. Open up the e-hentai.org folder*, and you’ll see some cookies listed. The ones that are relevant to your login session are ipb_member_id, ipb_pass_hash, and ipb_session_id.
Copy these three cookies into HDoujin Downloader using HDoujin Downloader’s cookie editor (instructions here). Use “exhentai.org” or “e-hentai.org” as the domain, and copy-and-paste the “Name” and “Content” fields as shown in your browser for each cookie.
You have the option of marking each cookie as Persistent. If enabled, HDoujin Downloader will maintain the cookies between sessions so that this process will only need to be repeated when the cookies expire.