Well, it happens to me several times. Here are my solutions when occurring to this problem:

Solution 1: Update Raid: Shadow Legends to the Latest Version.

Solution 2: Check For Server Outrages.

Solution 3: Change the Mode of Connection.

Solution 4: Scan and Repair Files.

Solution 5: Disable Proxy Server.

Solution 7: Reset Network Configurations.

But I just starting the journey in Raid: Shadow Legends, before that I have been playing WoW Classic. And I ALSO Can't connect to servers sometimes. I remember at this one time, I can't connect at all, it logs me in, sits on "Connected". When I hit cancel to go to the server list I try picking one then it says I've been logged out. So I was wondering if it is a compatibility issue? Since when Blizzard let this thing happen? I mean I understand why you forbid us from buying wow classic gold, ( have bought them anyway), but this? Unacceptable!

I have tried to update my drivers and operating system, no luck. Anyone?