Hi @Ma_01 ,
Please check this community thread in regarding to Cloudera Manager 6.1 Express functionality change:
https://community.cloudera.com/t5/Product-Announcements/ANNOUNCE-Cloudera-Manager-6-1-Express-functionality-change/td-p/84180
In short, from Cloudera Enterprise 6.1 and higher, we are limiting Cloudera Express customers using both CM6 and CDH6 to a maximum of 100 deployable nodes across all of their environments.
Thanks and hope this answers your question.
Li