The main issue is about DeepL not answering at all or answering with an http error code like 401, 403, 500 or alike. This also implies, that the user should see the error message, coming from DeepL.

Also important is to think of the document translation in InstantTranslate. There the user should also see the message, when the document translation is done / or actually not done. Currently he is getting offered a document for download and translate5 says, it is ready, but actually if he tries to download he only gets an export-error.txt file. That is really bad.

It should be implemented in a way, that it also works for other integrated MT language resources.