I'm not sure if I can help you but:

Do you have an iPhone and have app version 23.1.0? (Go to More, scroll to the bottom). I'm asking since there seem to be more problems with it lately than with the Android version.

Also, go to More > Settings, scroll to the bottom and enable error logging, which may help customer service.

From older messages, such as this one, I understand that restarting the app should normally help.

I'm not sure if switching to a paper version is possible after you've started to use it. In any case, that should be done via customer service. Do mention you're currently travelling, since that means you're in the most urgent category.

Hi rvdborgt,

Thanks for your answer. Yes, it’s that version indeed.
Restarting worked before, but since adding the manual journey to Antwerp, the journey itself doesn’t appear and I can’t add new journeys anymore - and therefore no QR code is generated for today. 
 

I did already contact about other issues with the QR codes, via Facebook Messenger. But the biggest problem is that they are not answering at all - waited more than a week, and I did mention that I’m currently travelling. 

Do you have a continuous pass? In that case, you can at least show the ticket inspectors that you have a continuous pass (under My Pass) and that you're not fare evading.

If you have any extra costs, then Interrail will have to pay them. Keep all receipts.

Thanks, yes I’m traveling with the 3 month pass. And I’m continuing my journey like you explained. Up to now I haven’t received a fine. It helps that I at least can show the QR code of the earlier travel days.
 

Hi Sebastian, As mentioned in a previous thread, I escalated this internally. Cheers,