What do you need to do first?

You need to modify the .htaccess file in the main root of your WordPress directory.

# START LiteSpeed Timeout Solution
php_value upload_max_filesize 128M
php_value post_max_size 128M
php_value max_execution_time 300
php_value max_input_vars 3000
php_value memory_limit 256M

<IfModule Litespeed>
SetEnv noabort 1
SetEnv noconntimeout 1
</IfModule>

set_time_limit(1500)
# END LiteSpeed Timeout Solution

Once completed make sure you refresh your page so it uses the new rules from .htaccess

Your issue should now be resolved!