vim-solarized 8 doesn't show correctly in tabby

[lixiaoquan]

Describe the problem:
Please take a look at following pictures, the 'gray' color in vim-solarized 8 seems not show correctly in tabby

both pictures are got from a nvim in a ssh session to a remote server (in the same tmux session).

Colorscheme is solarized8_flat from vim-solarized8

This one is from tabby

This one is from window terminal

I think the color rendered in windows terminal should be correct, I also get same result from kitty

To Reproduce:

1. Use tabby to login to a ssh session
2. Use nvim 0.8.3 with nvim-solarized 8
3. Edit any .py file and use # comment to generate text with light gray characters

Is there any configure I missed?