if you bought it over the weekend, social features were temporarily disabled (which this patch fixed), meaning there was no login required. now it is back to normal, so you have to log in with your LE account. you can connect the one you posted from to steam (go to My Account in the top right corner of the forum) and use that.
character saves are currently local so you should not lose any progress.
Chat has… changed just in the last month while I’ve been playing. It’s definitely WoW Barrens chat these days 
Good you got it fixed anyway and specially great that you got the “other device” thing sorted out. My first thought when I saw that error message was that I had been hacked. Very happy it was just a bug.
the thing is i bought by steam a week ago and i play a few days with the standalone client and no login was required and i created my LE account before and i linked to steam after that , but now with this patch i cant login because mu LE account appears without game license
hmm that sounds like there could be something else going on… try relinking your steam account from the page linked in this article, and if that doesn’t work, contact support (link is also on this page): http://support.lastepoch.com/article/160-steam-account-linking
how , that article only says something i already know but i dont found any link my steam to my LE account
there’s a link to this page: https://lastepoch.com/player/account/overview
you should see a way to link your steam account there, if not hopefully support can get things sorted out. 