Strange. If I use @plebstr with this npub I am unable to successfully add any relays. If I use it with @pinecones npub I can add relays without issue. I'm unable to make any sense of this.
Discussion
Hmm, seems like there is a problem with signature or something around it while creating event that stores relays. I will look into that super soon and try to fix that 😊
Sorry for inconvience
I was just testing the app, I personally try to stick with using open source software if I'm able. Plebster does seem to be fairly popular tho, so I thought it worth mentioning for those who don't mind using a closed source client.