^ can you try login process again with a different browser
given test user account is working fine for me. tried login, browsing & logout a few times.
I tried with internet explorer. I typed "tammelinn.eu". And it stiil didnt let me login
Should i go with
https://tammelinn.eu?
it is fine if you have configured now talk to your host provider to make rewrite rule to your host.
If you use google seo set changes on plugins area to your htaccess file or add ypur rewrite rule from not https to https i tell to my host provider and now works.