Yes, I tried to remove the account and add it again. Tried to add the google account as a Microsoft Outlook and the error persists. I see on the web that uninstall skype should address this problem but didn't work too.
The contacts and calendars are all syncing well.
Just the e-mail doesn't work.
I'm a bit frustrated with this. The amber takes a few improvements to WP8, but my e-mail is very important to me.
Thank you for your kind reply!