Greek Characters

I make an app in app inventor for greek students. All the data are in greek characters. When I write direct to airtable accept full greek characters. When I try to write from app inventor the data in airtable are in a strange form.
I make encode and decode in appinventor soI have the possibility to see the greek characters in appinventor . But I also want to see the same data in airtable.
Thanks to all