I've had so many problems with accessing 'favourites' on PeakD that I thought it was a bug in PeakD's code. I asked in their Discord and they just said 'It's a node problem and you might have too many favourites'. So I started investigating.
Some people think it's a bug with the server code & some people think the node operators aren't focused/skilled enough.
I don't know exactly because I haven't ever run a node, but I do know that I get the peakD bug even when I only have 3 favourites on a new account, so that suggests to me that it's a bug with PeakD.
So.. no fixes for anything, but the first step is always awareness of the problem!