Please go to define code string to confirm which code part you have setup with a function of curr balance --- then go to code part values -- click on that code part and make sure you have USD setup and that the voucher date falls within the valid from to dates on this code part

Hi @Nancy Fink , Thank you very much for the quick response.
I have checked the mentioned windows and noticed that there is no tab for Code H.
How can I add that code part?
 

Per your define code string -- code part H you have called currency.  

Per your code part value screen -- looks like you do have the tab for currency with only GBP setup.  You need to add USD in this screen and make sure you use correct valid from and to dates

Thank you @Nancy Fink for the detailed explanation.

I really appreciate your help.

Hi @Nancy Fink, Do you have any idea how to approve this voucher after fixing this issue.

I tried with Update GL Voucher but this voucher wasn’t there.
 

please go to voucher entry -- query voucher -- on voucher status -- use drop down to set to approved. 

NOTE:  your user group will need to be on the voucher series per voucher type -- RMB to user group and make sure is set to enter and approve

Thank you very much Nancy, I could approve the vouchers.

Thanks again