Error message when settling bill

I get the following error message when trying to settle a bill,same for cash, card and voucher.

was working perfectly, just stopped working during service.

any ideas what it could be ?

Perhaps it’s your database?

Payment process rule?
Device/intervrated machine incorrectly configured?

I have never seen that message. Best guess is the connection to the database was blocked.

Post the content of the log file:

[Documents]\SambaPOS5\log.txt