for anyone else that runs across this post for the same error reason when trying to delete pages from the /Host/ menu,

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Error: is currently unavailable. DotNetNuke.Services.Exceptions.ModuleLoadException: The argument 'portalId' cannot be negative. Parameter name: portalId ---> System.ArgumentOutOfRangeException: The argument 'portalId' cannot be negative. Parameter name: portalId at DotNetNuke.Common.Requires.NotNegative(String argName, Int32 argValue) at DotNetNuke.Entities.Tabs.TabVersions.TabVersionSettings.IsVersioningEnabled(Int32 portalId, Int32 tabId) at DotNetNuke.Entities.Tabs.TabChangeSettings.GetChangeControlState(Int32 portalId, Int32 tabId) at DotNetNuke.Entities.Tabs.TabController.SoftDeleteTabInternal(TabInfo tabToDelete, PortalSettings portalSettings) at DotNetNuke.Entities.Tabs.TabController.SoftDeleteTab(Int32 tabId, PortalSettings portalSettings) at Dnn.Modules.Tabs.ManageTabs.DeleteTab(Int32 deleteTabId) at Dnn.Modules.Tabs.ManageTabs. (EventArgs e) --- End of inner exception stack trace ---
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what worked for me as a workaround was to go into the database to edit the records for those pages
TABS table
edit the record to IsDeleted = True, PortalID = 0

then, after clearing the cache on your site, you can go to the Admin > Recycle Bin and can proceed to full-delete the pages from the site by Emptying the Recycle Bin