How to update mysql-server 5.5 to 5.7

    Hello,


    i installed a fresh version of the current imscp.
    I tried to install the Mysql-Server Version 5.7 with the following command: ./imscp-autoinstall -dr sql
    But i get the following error:
    [ERROR] autoinstaller::Adapter::DebianAdapter::_processAptRepositories: gpg: requesting key 5072E1F5 from hkp server keyserver.ubuntu.com
    gpg: keyserver timed out
    gpg: keyserver receive failed: keyserver error


    /edit
    # ping keyserver.ubuntu.com
    PING keyserver.ubuntu.com (91.189.90.55) 56(84) bytes of data.
    64 bytes from cassava.canonical.com (91.189.90.55): icmp_seq=1 ttl=51 time=44.0 ms
    64 bytes from cassava.canonical.com (91.189.90.55): icmp_seq=2 ttl=51 time=44.6 ms


    The server is reachable



    Server Version: Debian Jessie
    i-MSCP: 1.2.17



    Any suggestion to fix this?