Expense Report Approval - transaction is being processed by Integration Broker (10502,542)

A user Approved an Expense Report. She approved it by going to the following navigation: Travel and expense> Approve Transactions > Approve Transactions.

After approving she received an email with the subject Expense Report 0000001510 could not be Approved. The body of the email contained the following sentence: Expense Report could not be approved due to system error. Please contact your system administrator.

The email contained a link below a sentence that said: You may navigate directly to the expense report approval page by clicking the link below. The link was similar to https://www.domain.edu/psp/F92PRD/EMPLOYEE/ERP/c/APPROVE_EXPENSE_TRANSACTIONS.EX_SHEET_APPR.?Page=EX_EXPENSE_APPRV&SHEET_ID=0000001510