And after adding a PWR_FLAG like below, ERC is satisfied again:
I could not find that other connector symbol in KiCads libraries (but also did not search very hard).
I am missing an essential part of the error message in that screenshot.
It says: Pin1 (Power output) of component #FLG0120 is connected...
and there the screenshot cuts off. Connected to what?
For ERC the rules are pretty straightforward. When there is a pin with type “Power Input” (such as a GND symbol) connected to a net, then that net must also have a single “Power Output” pin. Connecting multiple Power Output pins together is also prohibited for ERC.
If you look at the “Conn_Coaxial” symbol in the symbol editor (hover over it in Eeschema and press [Ctrl + e]) then both pins are set to passive:
And passive pins can be connected to anything except an “Unspecified Pin” or a “No Connection” according to the default ERC matrix:
To check if there is anything fishy with your other connector, then also check it’s pin types in the symbol editor, or post the project here. If posting, then zip the whole project inclusive the “ProjectName-Cache.lib” file. (Did you use connector symbols from the default libraries or did you modify them in any way?
Yes, thanks. I understand this and as I stated in the previous post, it works as it should in 5.99. I think either the file got corrupted (?) or there was a bug in the 5.1.8 release. I did not make any modifications to the library symbols.