eWon Flexy -> eSync / DataMailconnector configuration problems

Right now we are working for a client to look at the opportunities to make daily insight into the level of different tanks. The tanks are spread over different locations in Europe, and all have an eWon flexy 201.

All these eWons are linked to one and the same account. And accessible via the ecatcher application.
To have sought information about the possibilities
for this we came out on the eSync application.

Before we want to implement this change etc. we first installed the eSync application locally on a laptop. And the manual is followed step by step.

However, we always get the following error message: “httpc-http connect error”

(The IP address of the laptop on which eSync is installed has been determined by means of the IPCONFIG function in the CMD prompt of Windows).

Then we came up with the following topic: Accessing tags via eSync

Following this we went to try the DataMailbox connector which is also mentioned in the above mentioned topic. However, we do not have a developer key at this time.
We did, however, follow all the steps from this document. And we also manage to actually create a log file, but the file gives the following error message: “DmwebApi ERROR Failed to syncdata : 400 - Missing argument ‘t2maccount’ for method parameter of type String”

Our question is mainly what goes wrong now, and which configuration is not right at the moment.
And if eSync actually offers the possibilities the wishes of the customer.


The httpc-http connect error means that the eWON could not find the eSync server. Typically this means they are not on the same network or there is some kind of firewall set up on the server that is blocking connection. What is the IP address of your eSync server Flexy?

A developer key is required for DataMailbox. The error you received with the DMWebAPI indicates that you’re missing your talk2m account information in the API–if you do not have a developer ID, this could be why.

Have you requested a developer ID from our website, developer.ewon.biz?

Are there also any costs associated with a developer ID?


No, there is not a cost associated with a developer ID. Looking at your screenshots, your WAN interface and your eSync server are in the same network. Have you checked the firewall settings on the server to ensure it is not blocking any connection attempts?


To confirm as I think there is a bit of confusion here.

Are you using a standard eSync installation or eSync in conjunction with the Data Mailbox?

Would it be possible to see the Data Managment setup tab of your eWON?

First we tried the standard eSync installation, when we came across some problems. And were looking for a solution, we came across the Data Mailbox.

But we will request a Developer ID, and look into the firewall settings.

Thanks in advance.


As @ashley_hms mentioned, it definitely appears as if there are some firewall restrictions on the server hosting eSync.

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We got the DataMail connector up and running yesterday. We are also able to view the values of the tank with the “Talk2M DataMailbox Viewer”.

Currently we are looking for a solution to view the tank levels from different location on a webpage. Or to send a email notification twice a day.


Are you trying to view them from the eSync backend or from the Data Mailbox RESTful API? In either scenario some level of development is going to be required in order to create a webpage to visualize that data.

We’re currently using the DataMailbox.


You will absolutely need a developer if you would like a front-end to visualize this data. This is going to require building some platform to read from the REST api.

Unfortunately I cannot provide that code here for support though HMS is always available to provide technical services to aid in developing your project.