Problèm of identity/connection

I am presently connected to Loomio under name xaviervz username xaviervz, with an email adress A. But when I try to connect with another computer on this same account xaviervz with email A, be it with password, be it whith link sent on email A, I reach a page where I am connected with xaviervz4 and member of none of my groups.
In the "edit profile" section, I can read :
* name xaviervz
* username xaviervz4
* email emailA

If I type a gmail adressl, one never used for loomio, and click "update profile", it consistently replies : "has already been taken"

With another non gmail adress emailB, it updates correctly.

If I try then to connect and type emailA, it asks me "saisissez le noms sous lequel vous voulez intervenir, et nous vous enverrons un lien de connection". (type the name under which you want to contribute and we'll send you a connection link)

What should I do?

W

Is it clear? Any hint? Thanks