I am not sure what feature you are talking about with twitter in your sidebar. Can you provide an URL?

http://www.farcom.com/LD/blog1.php

you will see it on the right / bottom side.

OK, that's not a b2evolution feature but a feature of the mystique skin. You'll have to ask @sam2kb about it ;)

There's a chance that twitter changed their API. The skin was released over 3 years ago :)

See if you can get this to work
https://twitter.com/settings/widgets/

Hello.

First I would like to praise and say I love the b2evolution. Use for 5 years. :D

I have this same problem with the Skin Mystique.
In the sidebar of my blog, version 5.0.5-stable released on 02/Aug/2013, have the box "My latest tweets" but just stays loading and do not carry the tweets.

You told me to look the part of Twitter. I looked.
Now I need help to know in which file I need to modify this API.

I love the Skin Mystique and I don't intend to change.

Thanking you in advance!

Twitter has discontinued its unauthenticated v1.0 API, so this widget has stopped working as of 2013-06-11.

Twitter wants your only option for on-page widgets to be their own Embedded Timelines, but there are workarounds which involve installing server-side code to support this widget.

Here is the work around:
https://github.com/StanScates/Tweet.js-Mod