Tab compleation in command mode stops working

The tab compleation in command mode randomlly stops working every now and again. I have not noticed any errors that trigger this. I do have some compleation plugins that probably have someting to do with this:

Plug 'hrsh7th/nvim-cmp'
Plug 'hrsh7th/cmp-nvim-lsp'
Plug 'hrsh7th/cmp-buffer'
Plug 'hrsh7th/cmp-path'
Plug 'hrsh7th/cmp-cmdline'
Plug 'hrsh7th/cmp-nvim-lua'
Plug 'onsails/lspkind-nvim'

My question basically is, who do I go by debugging something like this and or how does the command mode compleation work?

Any :h pages I should read that could help me?

Kind Regerds