Having trouble connecting to discuss.tchncs.de

I'm trying to subscribe to https://discuss.tchncs.de/c/askelectronics but it seems that if I search in communities (yes under all) for askelectronics or even if I manually enter the url ( https://lemm.ee/c/askelectronics@discuss.tchncs.de ), I get a community not found error

Anyone have any idea what's going on here?