In Hyperledger Fabric, how do I join a channel if I cannot use the peer channel fetch command?

It turns out that I needed to add the orderer parameter -o. Additionally, since I was connecting with TLS, I needed to specify --tls true as well as specify the --cafile.

The full command is as follows:?

peer channel fetch 0 -c mychannel -o orderer.example.com:7050 --tls true --cafile $ORDERER_CA