Problem with sync calibre and obsidian

I have a problem with the sync between calibre and obsidian.
I have this error: “Failed to communicate with “/interface-data/init?16xxxxxxxx610”, with status: [400 (error)] Bad Request
Failed to parse header line”

I have in the server address “http://localhost:8080” and I have the error. If I change to my IP adress to my server address: “”, then does not appear an error but does not appear anything.
Please, anybody have a solution for this problem

Thank you in advance.

I fixed it, I used in the driver address http://192.XXX.1.XXX:8080 and it worked. I hope this help somebody