Connecting to local kobotoolbox installation

I have installed kobotoolbox on my Ubuntu 18.04 PC using the local (workstation) configuration . I can add projects and design forms from my PC .But I keep getting the error “Form listing failed.Error: refused while accessing” while I try to connect using kobocollect from my android phone.
Again If I remove the port number which is 8000 I get “Form listing failed.Error: responded with :No Content (204)”
Do I have to install kobotoolbox using the server configuration in order to connect from my phone if not , whats the problem? I have checked everything… the ip address is correct , no firewall is running in my Ubuntu PC.