This article will explain you the cause(s) and solution(s) for this console error.
Error in console:
SEVERE Found a duplicate mod [MODINFORMATION]
A mod is installed twice. (Two of the same mods are installed).
Delete the duplicate mods from the "mods"folder via the "FTP File Access" section on the Multicraft panel or by using an external FTP client like FileZilla or WinSCP.