Solution : https://service.sap.com/sap/support/notes/492233 (SAP Service marketplace login required)
Key words :
prerequisites saving alert monitor settings, message class /sapapo/amon, alert monitor initial screen, authorization object c_apo_amon 'apo, alert monitor settings, /sapapo/amo_standard reason, program /sapapo/saplastand, messages 001 'settings &1 transferred, change default settings', alert monitor