The screen split prefix set in tmux does not work

 set-option-g prefix C-a
bind-key C-a send-prefix

# split panels using | and -
bind | split-window-h
bind-split-window-v
unbind '' ''
unbind%

# force a reload of the config file
# reload config file (change file location to your tmux.conf you want to use)
bindr source-file through /.tmux.conf

# quick panecycling
unbind^A
bind^A select-plane-t:.+

# smart pane switching with awareness of vimsplits
bind-n C-h run "(tmux display-message-p'#{pane_current_command}' | grep-iq vim & & tmux send-keys C-h) | | tmux select-plane-L"
bind-n C-j run "(tmux display-message-p'#{pane_current_command}' | grep-iq vim & & tmux send-keys C-j) | | tmux select-plane-D"
bind-n C-k run " (tmux display-message-p'# { pane_current_command}' | grep-iq vim & & tmux send-keys C-k) | | tmux select-plane-U"
bind-n C-l run " (tmux display-message-p'# { pane_current_command}' | grep-iq vim & & tmux send-keys C-l) | | tmux select-plane-R"
bind-n C-\run "(tmux display-message-p'#{pane_current_command}' | grep-iq vim & & tmux send-keys 'C-\\') | | tmux select-plane-l"

# resize pane
bind-n C-Down resize-plane-D5
bind-n C-Upsize-pane-U5
bind-n C-Right resize-plane-R10
bind-n C-Left resize-plane-L10

bind-n S-Down resize-plane-D1
bind-n S-Upsize-plane-U1
bind-n S-Right resize-plane-R2
bind-n S-Left resize-plane-L2
# tmux status bar color
set-option-g status-keys "emacs"
set-g status-left-length 50
set-g status-right "Show Terminal # (date'+%a, %b%d-%I:%M')"

bind c new-window-c "#{pane_current_path}"

set-grenumber-windows on

bind-key b break-plane-d
bind-key C-j choose-tree

# Use vim keybindings in copy mode
setw-g mode-keysvi

# Setup 'v' to begin selection as in Vim
bind-key-t vi-copy v begin-selection
bind-key-t vi-copy copy-pipe "reattach-to-user-namespace pbcopy"

# Update default binding of `Enter` to use copy-pipe
unbind-t vi-copy Enter
bind-key-t vi-copy Enter copy-pipe "reattach-to-user-namespace pbcopy"