.htaccess rules causing internal server error yet they look right - apache

Question

My server's. htaccess rules look like this:
RewriteEngine On
# first redirect
RewriteCond %{HTTP_HOST} ^www\.testing\.examplewebsite\.co\.uk$ [OR]
RewriteCond %{HTTP_HOST} ^testing\.examplewebsite\.co\uk$ [NC]
RewriteRule ^(.*)$ https://testing.examplewebsite.com/$1 [L,R=301]
# second redirect
RewriteCond %{HTTP_HOST} ^www\.test\.examplewebsite\.co\.uk$ [OR]
RewriteCond %{HTTP_HOST} ^test\.examplewebsite\.co\uk$ [NC]
RewriteRule ^(.*)$ https://test.examplewebsite.com/$1 [L,R=301]
# Main redirect
RewriteCond %{HTTP_HOST} ^www\.examplewebsite\.co\.uk$ [OR]
RewriteCond %{HTTP_HOST} ^examplewebsite\.co\uk$ [NC]
RewriteRule ^(.*)$ https://examplewebsite.com/$1 [L,R=301]
# All subdomains that don't exist redirect
RewriteCond %{HTTP_HOST} ^(.+)\.examplewebsite\.co\.uk$ [NC]
RewriteRule ^ https://www.examplewebsite.com/ [L,R]
But for some reason none it causes a server internal error, I'm not sure if they are all 100% correct either. Like the last rule, should that too use ^(.*)$ at the start and $1 at the end
Same for the flags, not too sure if they are all correct.
Basically I am trying to make:
testing.examplewebsite.co.uk and www.testing.examplewebsite.co.uk go to https://testing.examplewebsite.com
test.examplewebsite.co.uk and www.test.examplewebsite.co.uk go to https://test.examplewebsite.com
Some other subdomains like above
examplewebsite.co.uk and www.examplewebsite.co.uk go to https://examplewebsite.com
Make all used domains, for example stackoverflow.examplewebsite.co.uk and www.stackoverflow.examplewebsite.co.uk both be sent to https://examplewebsite.com

Answer 1

You have a typo in all of your conditions. the 2nd conditions in your lines is missing a . before uk. ^testing.examplewebsite.co.uk$ [NC]
RewriteEngine On
# first redirect
RewriteCond %{HTTP_HOST} ^www\.testing\.examplewebsite\.co\.uk$ [OR]
RewriteCond %{HTTP_HOST} ^testing\.examplewebsite\.co\.uk$ [NC]
RewriteRule ^(.*)$ https://testing.examplewebsite.com/$1 [L,R=301]
# second redirect
RewriteCond %{HTTP_HOST} ^www\.test\.examplewebsite\.co\.uk$ [OR]
RewriteCond %{HTTP_HOST} ^test\.examplewebsite\.co\.uk$ [NC]
RewriteRule ^(.*)$ https://test.examplewebsite.com/$1 [L,R=301]
# Main redirect
RewriteCond %{HTTP_HOST} ^www\.examplewebsite\.co\.uk$ [OR]
RewriteCond %{HTTP_HOST} ^examplewebsite\.co\.uk$ [NC]
RewriteRule ^(.*)$ https://examplewebsite.com/$1 [L,R=301]
# All subdomains that don't exist redirect
RewriteCond %{HTTP_HOST} ^(.+)\.examplewebsite\.co\.uk$ [NC]
RewriteRule ^ https://www.examplewebsite.com/ [L,R]