WowAce

When I log into Classic I am greeted with the following LUA:

Message: ...terface\AddOns\DataStore_Agenda\DataStore_Agenda.lua:651: attempt to index global 'C_Calendar' (a nil value)
Time: Thu Apr 30 17:56:44 2020
Count: 1
Stack: ...terface\AddOns\DataStore_Agenda\DataStore_Agenda.lua:651: attempt to index global 'C_Calendar' (a nil value)
...terface\AddOns\DataStore_Agenda\DataStore_Agenda.lua:651: in function <...terface\AddOns\DataStore_Agenda\DataStore_Agenda.lua:633>
[C]: ?
...ddOns\GatherMate2\Libs\AceAddon-3.0\AceAddon-3.0.lua:70: in function <...ddOns\GatherMate2\Libs\AceAddon-3.0\AceAddon-3.0.lua:65>
...ddOns\GatherMate2\Libs\AceAddon-3.0\AceAddon-3.0.lua:527: in function `EnableAddon'
...ddOns\GatherMate2\Libs\AceAddon-3.0\AceAddon-3.0.lua:620: in function <...ddOns\GatherMate2\Libs\AceAddon-3.0\AceAddon-3.0.lua:605>
[C]: in function `LoadAddOn'
Interface\FrameXML\UIParent.lua:353: in function `UIParentLoadAddOn'
Interface\FrameXML\UIParent.lua:424: in function `TimeManager_LoadUI'
Interface\FrameXML\UIParent.lua:693: in function <Interface\FrameXML\UIParent.lua:658>

Locals: <none>