ElecCore 1.8.9-1.4.247 Error due to a Mod Rejection

[01:00:43] [Server thread/ERROR] [ElecCore]: A player disconnected from the server without connecting first!
[01:00:43] [Server thread/ERROR] [ElecCore]: Player: TextComponent{text='', siblings=[TextComponent{text='MastaC729', siblings=[], style=Style{hasParent=true, color=null, bold=null, italic=null, underlined=null, obfuscated=null, clickEvent=ClickEvent{action=SUGGEST_COMMAND, value='/msg MastaC729 '}, hoverEvent=HoverEvent{action=SHOW_ENTITY, value='TextComponent{text='{name:"MastaC729",id:"a429545b-8b0d-4412-ae57-33ee3cb0042a"}', siblings=[], style=Style{hasParent=false, color=null, bold=null, italic=null, underlined=null, obfuscated=null, clickEvent=null, hoverEvent=null, insertion=null}}'}, insertion=MastaC729}}], style=Style{hasParent=false, color=null, bold=null, italic=null, underlined=null, obfuscated=null, clickEvent=ClickEvent{action=SUGGEST_COMMAND, value='/msg MastaC729 '}, hoverEvent=HoverEvent{action=SHOW_ENTITY, value='TextComponent{text='{name:"MastaC729",id:"a429545b-8b0d-4412-ae57-33ee3cb0042a"}', siblings=[], style=Style{hasParent=false, color=null, bold=null, italic=null, underlined=null, obfuscated=null, clickEvent=null, hoverEvent=null, insertion=null}}'}, insertion=MastaC729}}