The export fails when an expense is dated before the opening date of the balance in Datev (Datum Anfangsbestand). For example, an expense from June 1st cannot be exported into an account (Kasse) which starts on June 15.
While it’s possible to re-open accounts for certain accounting tools, this is generally not possible in Datev. There are two alternative solutions:
To create a new account (Kasse) in Datev which fits the time frame of the expenses that need to be exported from Pleo.
Create the expense in Datev manually (having downloaded the receipt over from the Pleo expense). Next, remove the expense from Pleo by switching to the generic format and then reconnecting to Datev.