Solution : https://service.sap.com/sap/support/notes/146382 (SAP Service marketplace login required)
Key words :
additional key words sapphone, simplified work center maintenance, maintain work center settings, area code-extension combination, incorrect area code, dialog box 'maintain, allowed extension, telephone number', program error, standard system
Related Notes :
378259 | SAPphone: No authorization for initial tel.no. |
178241 | SAPphone: Extension check with incorrect server |