When I am going to make a translation of a text, a box appears saying no translation was found to what is this?
It could happen if you still don't visit the related page in its translated language.
Try to visit all pages of your website in its translated language and try again.
Also, make sure you didn't reach your limit of translated words. If it is the case, it could explain why some of your texts are not translated (and why you can't edit their translations). You can see your number of translated words in your Weglot Dashboard (https://weglot.com/dashboard) under "current usage".