@Hubzilla Development
I've been messy with connect/follow this channel... So I've deleted the contact on my list to better add now, but I think I've bugged it because no more connect/follow button is showing :(

Sorry for this noob question, starting here :)
Or may be there's a spot where I can ask this question...

Thx for your help.
oh lol I just posted this issue without reading your post xD
Find the 'reddress' (*) aka user@host of the person. It should be visible on their profile someplace. Visit your Connections page and enter this in the box in the top left.

(*) we used to call this a 'webbie', but in Spanish 'red' means 'network' so it makes more sense and is kind of whimsical name for a network address.