login problem

I just had this happen.
In my case it was caused by my shortcut to login page missing www before the domain. This creates a mismatch in the wordpress_test_cookie Host.

SITE URL: https://www.domain.com
BAD LOGIN URL: https://domain.com/wp-login.php
Gives the message
ERROR: Cookies are blocked or not supported by your browser. You must enable cookies to use WordPress.

SITE URL: https://www.domain.com
GOOD LOGIN URL: https://www.domain.com/wp-login.php
No Error.

Hi thanks for the reply this did not work for me as the address was correct.
strange thing is when you login first time you get the message
ERROR: Cookies are blocked or not supported by your browser. You must enable cookies to use WordPress.
but when the second login box shows it works ok
really need to sort this as we use the members section to pass on information for 40 members that have read permission on the members page.

login directly from the site

From this I assume you have a login form on the frontend of your site generated by a plugin, theme or a text widget you have created.
For this to work your users will need to have the wordpress_test_cookie being set on the frontend pages.
The code which sets it is in wp-login.php line 435-439 (which is why you can log in on the second attempt)
You could try adding that code to your functions.php so that the wordpress_test_cookie is generated for all pages/posts.
This method would not work if you had a caching plugin caching output to html.

yes you are correct the login is by a plugin justin tadlocks https://www.ads-software.com/plugins/members/ it has not been updated for a while
it has worked fine untill a few days ago, and nothing has been updated or changed.
Anyhow thanks your advice and suggestion has worked fine.
thank you very much.

I do not have any instalations of the Members plugin at the moment but I can not see any support requests on www.ads-software.com about this issue, so it is possible that Justin is unaware of it.
If you want a solution from within the plugin it may be worthwhile making the plugin author aware of the problem.
A bug report made from
this url
should make him aware even though he does state that he does not answer support requests on www.ads-software.com (I think he still might read them)

Hi
i will post on the plugins forum, yes i knew he charges for support
one thing that has happened since i followed your advice is that when i edit a page the dashboard and page attributes,publish ect. flys in and out of side (just like windows 8 charms).
This happens in I.E and Chrome