First thing to note about Keepsolid is that their Wireguard is a bit flaky - your configurations may change without notice and will need to be regenerated in your management panel (they are aware of this “glitch” and are working on it, supposedly). However, it looks as though you have already done this.
So, your problem is most likely a time sync. problem. I have the very same on my Beryl - after a power down (overnight) my Wireguard client only reconnects after syncing the time in Luci (it does not sync correctly in the GL GUI). I am on 3.203 Beta5 but it appears to be a bug on 3.201 as well: