Invalid receipt

After using Codebook Pro for years, today I received a msg ‘Invalid Receipt: Codebook is in read-only mode. Tap here to visit the purchase page then tap Restore Purchases to refresh your receipt.

When I hit restore purchases it just flashes and nothing happens. Help?

@Kakirkla
Thanks for reaching out to us about Codebook and sorry to hear about the current issue with the receipt validation. Can you try from the Settings screen, tap on “View Purchases” and the Restore Purchases and see if that resolves the issue. If not, try rebooting the device and then try the validation again or log out of the App store and then log back in to see if that resolves the issue. If not, please reach out to us at support@zetetic.net for additional support, thanks.

Cheers,
Don

Don - I tried all of these solutions but none resolved the issue. Thanks Ken