It looks like you removed a language from your website, and you're trying to activate it again. Is that right?
If that's true, you can go to WPML → Languages → click Add/remove languages → select the language and Save.
If the issue does not get fixed, I would like to request temporary access (wp-admin and FTP) to your site to take a better look at the issue. It would be better to have a testing site where the issue is replicated.
You will find the needed fields below the comment area when you log in to leave your next reply. The information you will enter is private, meaning only you and I can see and access it.
Maybe I'll need to replicate your site locally. For this, I’ll need to temporarily install a plugin called “Duplicator” or "All in One WP Migration" on your site. This will allow me to create a copy of your site and your content. Once the problem is resolved, I will delete the local site. Let me know if this is ok with you.
IMPORTANT
- Please backup site files and database before providing us access.
- If you do not see the wp-admin/FTP fields, your post & website login details will be made PUBLIC. DO NOT post your website details unless you see the required wp-admin/FTP fields. If you do not, please ask me to enable the private box. The private box looks like this: hidden link
I'm looking into this and have logged into your site.
I could see the problem with the default language (Icelandic) being described as hidden, and missing from the main active languages list.
I ran a couple of troubleshooting steps that may have been expected to help here, but they did not.
I checked the settings within the database directly, where in the languages table Icelandic was marked as inactive, so I made an edit to mark it as active.
The hidden language message disappeared, but Icelandic was still missing from the list of active languages, and no default was specified.
I checked in with my colleagues, who recommended temporarily switching the default language to English, double-checking that Icelandic could be added as a site language, and then setting the default language back to the now active Icelandic.
But, after switching the default to English, Icelandic is still missing from the list of active languages, so I cannot set the default back to Icelandic.
I went back to the troubleshooting steps and flushed the WPML cache again, and now it looks to have worked, and I have been able to reset the default language to Icelandic.
I'm not sure how this problem arose, but it looks to be fixed now.
