Zoiper is a multi-platform softphone which offers contact integration, conferencing, encryption and more. The Community version is free but has limitations on some features, such as call transferring.
See Zoiper website for more information on Zoiper, or visit the Zoiper page on Google Play store.
If you are using Zoiper on Windows then please see the Zoiper for Windows Setup Guide.
For more in-depth information on setting up Zoiper please consult the help guides at the Zoiper Support Questions site.
If you can not register, check over your username and password, and that the SIP settings have been entered correctly .
Ensure SIP ALG is disabled on your router. See this page for further information.
If those are correct, also check your firewall settings.
If you are still not able to connect, contact SureVoIP Technical Support.