It said the postponement was due to "logistical reasons related to the COVID-19 pandemic" and a new date would be announced in due course.
Sierra Leone and Benin play their outstanding qualifier this month to determine the last of the 24 teams in the finals in Cameroon in January. The tournament has already been put back a year because of the pandemic.
CAF last month postponed the resumption of World Cup qualifiers, which had been scheduled for the opening weeks of June, blaming the COVID-19 pandemic.
The group phase of African qualifiers for the Qatar 2022 tournament is now due to start in September.
