Many thanks for the prompt reply. Appreciate others offering help.
I had gone through the processes you mentioned but without success and was on the point of giving up until I had what seemed like a daft thought, at least until I tried it.

I reset everything as previously but this time before starting Domoticz from the cmd line I cleared my web browser cache. When I started Domoticz this time it opened without a password. I have repeated this a couple of times and it seems that clearing the browser cache is a required step, at least on Windows. I mention this in case others have the same problem.

So, on with the build, two sensors working with a bridge. Time to scale up :~)

Can anyone help a newbie that has just built his first sensors, Gateway and Controller (Domoticz). I was pleased that I had managed to get everything working fine and started to see what else I could do with Domoticz when somehow I locked myself out. I certainly don't recall setting any passwords or even messing with those settings but now my Domoticz is requesting a username and password. I have tried the usual admin, admin and my windows password but it refuses to let me in. On the Domoticz website it suggests starting the program from shell with "./domoticz -nowwwpwd". Trying this starts the program but it still demands a password. I have deleted the program and reloaded but still it starts with a password request. Any ideas before I give up on Domoticz. My system is built around a Wondows 7 environment with Arduino Nanos and esp8266 for a gateway.