This is connection string URI example case:

mongodb://localhost:27017,localhost:27018,localhost:27019/sampleDb?replicaSet=rs0&socketTimeoutMS=5000

When trying to parse this example using ConnectionString::parse, receive the following error:

"Cannot list multiple servers in URL without 'replicaSet' option"

But if I change socketTimeoutMS to connectTimeoutMS everything is OK then.

Moreover, when specifying

mongodb://localhost:27017/sampleDb?socketTimeoutMS=30000&w=majority

Getting strange error too:

"Bad digit "/" while parsing 27017/sampleDb?socketTimeoutMS=30000&w=majority"

Looks like something is bad with socketTimeoutMS option.