Code changes done in X++ standard methods of RetailTransactionService* classes or added new methods in RetailTransactionServiceEx class are not visible by Real-Time Service – it stills executes an old code.
Possible solutions
Generate incremental CIL (sometimes full CIL) – this is a ‘must do’ step, because all Real-time service calls are executed in CIL;
Restart Real-time service web site and application pool in IIS;
Restart Windows Process Activation service on the machine where Real-time service web site is installed.