[Error Message] Change Avatar

[ClementSaubois]

Hello,

I have a forum on MyBB  and when I want to change my avatar I have a 500 error.

Log error : http://paste.clementsaubois.fr/jSesRUVMkz 

Environment : 


PHP 7.0.10
MyBB 1.8.7
MySQL 5.5.5

waiting for your reply

Cordially

Clément