Here is the LUA error I receive upon loading into the game:

Message: Interface\AddOns\SexyMap\SexyMap.lua:587: Attempt to register unknown event "PET_BATTLE_OPENING_START"
Time: Sun Sep 15 12:12:43 2019
Count: 1
Stack: Interface\AddOns\SexyMap\SexyMap.lua:587: Attempt to register unknown event "PET_BATTLE_OPENING_START"
[C]: in function RegisterEvent' Interface\AddOns\SexyMap\SexyMap.lua:587: in function SetupMap'
Interface\AddOns\SexyMap\SexyMap.lua:563: in function `?'
Interface\AddOns\SexyMap\SexyMap.lua:682: in function <Interface\AddOns\SexyMap\SexyMap.lua:681>

Locals: (*temporary) = {
0 =
}
(*temporary) = "PET_BATTLE_OPENING_START"

You're using the retail version of SexyMap on classic. Use the Twitch client to install the correct version and manage this for you.

Also in future, explicitly tell authors when you're playing classic.

Sorry--I'm a new user, so thanks for the heads up.