Cannot open invoices

I haven’t been able to open individual invoice screen neither for view nor edit over the last 2 weeks, on the cloud version of the app. Server returns status 500. Any ideas how to fix that?

Steps to reproduce the issue

Attempt to open any invoice on app.akounting.com E.g., https://app.akaunting.com/incomes/invoices/57062

Expected result

See the invoice form

Actual result

Returns message "Whoops, looks like something went wrong." Request URL: https://app.akaunting.com/incomes/invoices/57062 Request Method: GET Status Code: 500 Remote Address: [2606:4700:30::681b:b178]:443

System information (Akaunting, PHP versions)

app.akounting.com

In case, someone is having the same problem:

I've tried a bunch of speculative actions trying to get it working again. Finally, this seems to have resolved the problem:

1) duplicate an existing invoice

2) saving it

3) opening it from the list

now other invoices open too

how do you duplicate an invoice?

from Invoices list https://app.akaunting.com/sales/invoices
click on [...] button in "Actions" column
click on "Duplicate" item in the menu that opens up