During a recent installation on centos 7, on a deported database, It seems that the permission on the tuleap db user to access mediawiki were not set.

I had to run the following mysql command to solved this issue:

GRANT ALL PRIVILEGES ON \`plugin_mediawiki_%\` . * TO 'tuleap'@'ip.addr.tuleap.serv' identified by 'tuleap_db_passwd';