Please refer this link
https://kb.juniper.net/InfoCenter/index?page=content&id=KB10866&actp=search
Maximum number of MAC addresses—You configure the maximum number of dynamic MAC addresses allowed per port. As soon as the limit is reached, incoming packets with new MAC addresses are dropped. The MAC limit value in the EX-series switch default configuration is five MAC addresses.
Mark as accepted solution if find useful.
Thanks
Amit