Trouble single-logging in Wordpress

Hello,

I've integrated aMember Pro v4 with Wordpress 3.9.1 .
Content protection and the creation of WP user when aMember one is created work fine, but I can't single log to aMember and WP.

I've checked the FAQ here, and here are my checkings :

• Make sure that root urls in both aMember and Wordpress are use the same domain name. There can be issues if domains are different(for example www.example.com and example.com). Single login will not work if both scripts are installed on different domain names.

My general WP setup reads http://www.domain.fr
My aMember CP > Instal/config > Global reads http://www.domain.fr/amember

• Make sure that you have valid not-default security keys in wordpress config. (/wordpress/wp-config.php)

I changed the default keys

• Security keys in aMember's plugin configuration (aMember CP -> Setup -> Wordpress) must be exactly the same as in wordpress config (see above step).

I copy/pasted the keys inthe right place

• Check aMember CP -> Protect Content -> Integration and make sure that you set integration for Wordpress plugin.

• Also, just a note, single login will not work for users who have groups listed in aMember CP -> Setup -> Wordpress -> Admin Groups

Is there anything else that might be wrong ?
Thank you,
Hagop