When I am trying to add a node to the cluster we are getting the below error. Please let me know for any further information

qa_1:PRIMARY> rs.add("n7vgq1mhddbmgd02.general.disney.private:10001");
assert failed : error: local.system.replset has unexpected contents
Error: Printing Stack Trace
at printStackTrace (src/mongo/shell/utils.js:37:15)
at doassert (src/mongo/shell/assert.js:6:5)
at assert (src/mongo/shell/assert.js:14:5)
at Function.rs.add (src/mongo/shell/utils.js:1019:5)
at (shell):1:4
Sat Jul 11 08:46:56.898 assert failed : error: local.system.replset has unexpected contents at src/mongo/shell/assert.js:7