Trouble logging in with Twitter

Hi,

I’m all of sudden unable to login via twitter.
I get the following error:

Enter exactly the following url in Website and Callback Url options in your Twitter app (see step 3 here)
https://MYURL.com
Make sure cURL is enabled at your website server. You may need to contact the server administrator of your website to verify this
Make sure that “Enable Callback Locking” option is disabled. See step 4 here

The Website and Callback Url are both defined on my Twitter app settings and the Api keys are correct.
cURL is also enabled.
I can’t seem to find the “Enable Callback Lock” setting in Twitter App settings though..

The page I need help with: [log in to see the link]