ERROR: Cookies are blocked or not supported by your browser.

Try:
– Deactivating ALL (yes all) plugins temporarily to see if this resolves the problem (plugin functions can interfere). If this works, re-activate them individually (one-by-one) to find the problematic plugin(s).
– If you can’t get into your admin dashboard, try resetting the plugins folder by FTP. Sometimes, an apparently inactive plugin can still cause problems. Also remember to deactivate any plugins in the mu-plugins folder (if you have created such folder). The easiest way is to rename that folder to mu-plugins-old.
– switching to the unedited default Theme (Twenty Sixteen, etc.) for a moment using the WP dashboard to rule out any theme-specific issue (theme functions can interfere like plugins). If you don’t have access to your admin area, use FTP , or your web-host’s cPanel or whatever file management application your host provides (no Dashboard access required). Navigate to /wp-content/themes/ and switch to the default theme by renaming your current theme’s folder by adding “-old” to the end of the folder name. Alternately, you can remove other themes except the default theme. That will force your site to use it.
– If the above trouble shooting steps do not help, then try Enabling debugging and post the results.

Thank for this info. However, I have done all of the above and still no luck. Debug shows nothing and my browser has cookies enabled and tried different browsers. This is a fresh install so its using the default theme. Its strange.

Was wondering if I need to enable something in my Apache settings?

It’s more like to be a server sessions or cookie issue. Have you checked your server error logs?

Nothing in the server logs apart from access and general data. This is why I am perplex.

looks like something in server is filtering out the cookies that WordPress uses to handle logins.

Have you tried:
– Flushing any caching plugins you might be running, as well as server and/or browser caches. Also, any op cache or content network cache, as well as Cloudflare, clear those caches.
– deactivating ALL (yes all) plugins temporarily to see if this resolves the problem (plugin functions can interfere). If this works, re-activate them individually (one-by-one) to find the problematic plugin(s).
– If you can’t get into your admin dashboard, try resetting the plugins folder by FTP.
– switching to the unedited default Theme (Twenty Sixteen, etc.) for a moment using the WP dashboard to rule out any theme-specific issue (theme functions can interfere like plugins). If you don’t have access to your admin area, use FTP , or your web-host’s cPanel or whatever file management application your host provides (no Dashboard access required). Navigate to /wp-content/themes/ and switch to the default theme by renaming your current theme’s folder by adding “-old” to the end of the folder name. Alternately, you can remove other themes except the default theme. That will force your site to use it.

This does turn up in the access log:

“GET /wp-login.php?redirect_to=http%3A%2F%2Fmysite.co.uk%2Fwp-admin%2F&reauth=1 HTTP/1.1” 200 2426

I am at a point now where if I remove ?redirect_to=http%3A%2F%2Fwww.mysite.co.uk%2Fwp-admin%2F&reauth=1 FROM https://www.mysite.co.uk/wp-login.php?redirect_to=http%3A%2F%2Fwww.mysite.co.uk%2Fwp-admin%2F&reauth=1 I can enter my login details but all it does is reload the login page.

I can confirm that “siteurl” and “home” have the same address within the database.

EDIT – PLEASE IGNORE THIS POST AS I HAVE EDITED A WORDPRESS CORE FILE IN ORDER TO GET THE ABOVE.