Were sahabas used to read adhaan standing on kaaba?

Yes, it is reported that some of the Sahabah (companions of the Prophet Muhammad) would stand on the Kaaba to call the adhaan (the Islamic call to prayer). This practice was seen as a way to proclaim the message of Islam and gather the community for prayer. However, it is not a common practice today, and the adhaan is usually called from designated places such as mosques.