Errors when loading with dein plugin manager

[HaleTom]

I get the following (yes, sorry, it's garbled) output when trying to open a gist via Rawnly/gist.nvim:

COMMAND  SPELL  /tmp/3569585155.aria2-trackers-update   3% :1/29☰ :1 l
ugin/main.lua:
E5113: Error while calling lua chunk: Vim:Error invoking 'nvim_exec_lua' on chan
nel 3:
Error executing lua: vim/_editor.lua:0: nvim_exec2(): Vim(argadd):E479: No match

stack traceback:
        [C]: in function 'nvim_exec2'
        vim/_editor.lua: in function 'cmd'
        .../dein/.cache/vimrc/.dein/lua/server/server_functions.lua:75: in funct
ion 'unception_edit_files'
        [string "<nvim>"]:1: in main chunk
stack traceback:
        [C]: in function 'rpcrequest'
        ...avi/.cache/dein/.cache/vimrc/.dein/lua/client/client.lua:27: in main
chunk
        [C]: in function 'require'
        ...ar/ravi/.cache/dein/.cache/vimrc/.dein/lua/unception.lua:5: in main c
hunk
        [C]: in function 'require'
        .../var/ravi/.cache/dein/.cache/vimrc/.dein/plugin/main.lua:57: in main
chunk
Press ENTER or type command to continue

My config is:

let g:unception_block_while_host_edits = v:true
call dein#add('samjwill/nvim-unception')

Any ideas on how to use this with dein?