[Server thread/CRITICAL]: "Could not pass event 'pocketmine\event\level\LevelLoadEvent' to 'SignShop v1.1.3': Illegal offset type on SignShop\EventListener\LevelEvent"
[15:50:01] [Server thread/WARNING]: RuntimeException: "Illegal offset type" (E_WARNING) in "/var/mcpe/shared/Plugins/SignShop_v1.1.3.phar/src/SignShop/Manager/SignManager" at line 176

Signshop 1.1.3?!?!? That's a little out of date. I think that version was before our time! Try updating.