Cant register 'Not a valid email'

I dont know if this is a bug, but it's driving me crazy.

I have a hubzilla 4.6 installed (in a container, but so what). after lot's of fiddling, I managed to have a working sendmail solution on the host (well container). Running :

echo -n 'Subject: test\n\nTesting ssmtp' | sendmail -v dest.email@domain.dom

get the mail sent as expected.

But when I try to register, it keeps telling me that it's not a valid email. So I tried to disable email verification :

util/config system verify_email 0
sed -i '/verify_email/s/= 1/= 0/' /var/www/html/view/*/htconfig.tpl
echo 'App::$config['"'system']['verify_email'"'] = 0;'>>.htconfig.php
kill -USR2 1

(that kill force a reload of php-fpm, useless I know, but still) But I still get that message.

So I tried to configure the mail system by setting config[system][from_email] (using both util/config and the .htconfig.php) No change. So I tried to enable debuging by setting config[system][loglevel] = LOGGER_ALL and config[system][logfile] = /tmp/logtoitgeez. The file is not created. So I added these lines in the .htconfig.php :

error_reporting(DEBUG | E_ERROR | E_WARNING | E_PARSE );
ini_set('error_log','php.out'); ini_set('log_errors','1');

Still no dice. Help ?