I have worked with XML-RPC calls in the past to interact with MT in the past but after release of version 3.2 onwards I did not get a chance to work with it again, until recently. I used the Argotic Syndication Framework to interact with the MT XML-RPC. However I was constantly getting ‘Invalid login’ error even when I used the MT administrators details. I even tried using Fiddler to make sure that it was nothing in my code that was creating the issue. The method mt.supportedMethods returns all supported methods perfectly fine, however metaWeblog.getRecentPosts returned invalid login error.
After doing a lot of debugging I finally found out this documentation which indicates that each user has got a separate password for remote API. Once I changed the password for the user I was using to connect through the remote API, all started to work okay.
The way to alter this password is as under.
1. Log into MT
2. Click on your username in the top navbar to go to your profile
3. Scroll down to the bottom where you see “API Password”
4. Input the password of your choice and save. For security reasons, it should be different from your normal password
5. Use that password in your client software