Special characters in post request for rest API to my.openhab.org

I am trying to send a command to VoiceCommand, saying to turn on the lights but in my language I need to use a special character (å) to do this. If I send the post request directly to the openhab server (without my.openhab.org) it works fine, but if I am using my.openhab.org it doesn’t. If I send the command “tænd” it turns into “T�nd”.

What should I do to remove this error?

Try masking it for C/C++/Java:

In this case use:

Then I just receive \u00E5, is there an easy way to convert it back after I received it, other than checking for each special character?

Sorry, no idea.
For me it works to mask like:
geöffnet is masked to ge\u00F6ffnet