Please help "Crashed in OnStart with KeyNotFoundException: The given key 'SLKey' was not present in the dictionary."

hello guys I tried SO MUCH things but nothing worked, I just want to show the VOLUME calculated in ExecuteMarketOrderAsync on a label on the panel that the cBot will use to enter the trade, but NOTHING worked, I'm a newbie in c# and the code is not mine, he's the owner of the code: https://ctrader.com/users/profile/22207

please someone just give me a hint what I need to do 

the code is in the link (400+ lines)

https://justpaste.it/a9pn4