I didn't realize that I had to separate this line from the INDIHUB server:
INDI-Server: node-1.indihub.io:55518 and separate the host URL and PORT.
Once I took "node-1.indihub.io" and "55518" and place them into HOST and PORT sections, it started right up. I was pasting the whole line "INDI-SERVER: node-1.indihub.io:55518" into the Host block.