I was recently performing an eConnect installation as part of a eOne SmartConnect installation. The installation went as it should, but the service did not start after installation. Starting the service manually yielded this error:

The Event Viewer shows the following:
Unable
to bind to the underlying transport for [::]:80. The IP Listen-Only list may
contain a reference to an interface which may not exist on this machine. The
data field contains the error number.
The
eConnect for Microsoft Dynamics GP 2013 Integration Service service is marked as
an interactive service. However, the system is configured to not allow
interactive services. This service may not function properly.
Service
cannot be started. The handle is invalid
Here
is the three steps I used to solve the problem:
1. I verified that the service account used for the eConnect service is a local
administrator on the workstation.
2. I verified the eConnect User is setup in SQL and has sysadmin privileges, using SQL
Server Management Studio.
Here's a screenshot of how to check for this. Log in to the SQL Server > Expand Security > Right
click on the eConnect user > Click Properties > In the Properties
window click Server Roles. Ensure sysadmin role is checked. After granting sysadmin privileges, try starting the service.

3. I opened the "Microsoft.Dynamics.GP.eConnect.Service.exe.config" file in notepad, which
should be located in the following directory:
C:\Program
Files\Microsoft Dynamics\eConnect 12.0\Service
At
the bottom of the file, locate the following setting:
<serviceMetadata
httpGetEnabled="true" httpGetUrl=" http://localhost/Microsoft/Dynamics/GP/eConnect/mex
"/>
Change
the value for "httpGetEnabled" from "true" to "false". Save and close the file,
then try starting the service again.
After the final step, the eConnect service started for me.
Hopefully this saves you some time!
Adam Liposky
https://www.linkedin.com/in/adamliposky