The photoTAN-push procedure is currently not offered by comdirect for HBCI financial software. Use with Outbank is therefore not possible.
Allegedly, comdirect is working on a possibility: https://twitter.com/comdirect/status/1255033113098498048
Alternatively, you can use the mobile TAN procedure or the photoTAN procedure.
You can find detailed instructions for using the photo-TAN procedure here:
https://help.outbankapp.com/de/kb/articles/kann-ich-das-phototan-verfahren-in-outbank-verwenden