Like Joffm: Couldn't reproduce it on my LimeSurvey cloud server free plan (LimeSurvey Cloud Version 6.10.1, free plan) either.

Also worked fine on my installation on my own server.

Thank you very much for testing.
I upgraded my server to LimeSurvey Community Edition Version 6.10.1+250120 in the meantime.
I can export and import the survey without problems, but still no luck on the cloud server.

Things are a little bit strange...
Server message immediatly after clicking import:

500: Internal Server Error - Error: Failed to import survey language settings - data is invalid.
An internal error occurred while the Web server was processing your request.
Please contact Your Name to report this problem.

Base language of my survey is German, languages set are: German, English

Very strange:
The system imports "something" which shows up in the survey list:

    Survey ID    Status    Title    Created    Responses    Action    
    177893    Inactive         21.01.2025    0    

When clicking the "Edit" symbol or trying to delete the entry, I get the error message:500: Internal Server Error - Survey language not found - looked for en and deAn internal error occurred while the Web server was processing your request.
Please contact Your Name to report this problem.

The only way to get rid off the file is: Select item =>  Select "Delete" from the "Edit selected survey" => Delete

Cheers, Wolfgang


 

500: Internal Server Error - Survey language not found - looked for en and de

This sounds like LImesurvey couldn't finde German or English as a language in your installation.

Have a look into the general settings of your free tier and see what the language setting is.

Mine is like this:
 

My guess would be, that you did not allow German or English (which is strange, but that is what the error message sounds like to me).

However, I just switched my installation to another default language (not English nor German) and removed all other languages from the panel and I could still import your survey.

In any way, have a look at the language settings of your Limesurvey Cloud free tier, just to confirm what it looks like.

And if everything is OK with the languages, I would create a bug report. Or maybe open a support ticket, as it seems to be with Limesurvey Cloud.