Unable to upload historic data to new EmonCMS

I am installing a new, pre-configured emonpi with emoncms. I have an IotaWatt (that is currently and successfully posting to an older emoncms db on another RPI set up by myself). I also have two emonTHs, and planning to connect a pulse detector.

Problem is - I would like to have all historic data (since Jan 5 2019) loaded into the new emonpi. But the emonpi only uploads from the time of connection. This was not a problem with the other cms db. There I had few weeks or so of historic data on the Iotawatt before connecting it to the emoncms. It started catching up immediately, and was up to date after a couple of days. Not so with the pre-configured emoncms.

For some reason, the emopi detects three (named 0, 1, 15), all with the number of inputs broadcasted by the iotawatt. At some point it also added a node named iotawatt, and I configured all the 20 inputs on that one. The first time I tried, the emonTHs had been uploading data for some time, so the db was not empty.

I got a tip on deleting all feeds and inputs on the iotawatt node before setting the apikey, but that did not make any difference. I also tried deleting the inputs from the emonpi nodes, and also deleted inputs from the strange nodes 0, 1, and 15. They then disappeared.But still no luck.

What am I doing wrong?