) but it did not initialize the recaptcha.
Then trying an api key for the equivalent url http://xn--slja-loa.io which worked when reaching the site from http://xn--slja-loa.io but not .
Then I found the secure token which should work on all domains. It initialized the recaptchas on all domains and was also working on . https://developers.google.com/recaptcha/docs/secure_token
Edit
Since an api-key for http://xn--slja-loa.io is working from android when accessing the site from , it might be how the browser interprets the domain. Eg. firefox interprets as domain as http://xn--slja-loa.io as http://xn--slja-loa.io ?
Edit2
Edit3
I tried it just now and I am able to generate key for
6Ld8VRETAAAAALRXFNxmjEeVzbg2y5vdWv7THwJz
will post a complete working example shortly
EDIT 1
Here's git repo for code and same running on heroku
(however when earlier i tried it created a key for
too but on loading page at captcha it gives invalid domain
, figured out that was original issue, i thought you were not able to generate key for this domain)
Will try for a complete fix
EDIT 2
Btw you can specify your domain ip too, check this discussion
For me heroku free account doesn't provides ip of domain so it's difficult for me to test it
Also i was reading this thread
Figured out if i specify domains list as just com
it accepts. In your case, just specify se
as domains and it should work , google doesn't checks out exact url it just checks domain

Hope it helps, Will look into stoken
approach too