Async.runSync() returns error

[thdoan]

When I use Async.runSync(...), I get the following error on the client:

details: undefined
error: 500
errorType: "Meteor.Error"
message: "Internal server error [500]"
reason: "Internal server error"

When I switch back to Meteor.sync(...), everything works perfectly again, even though Meteor.sync() is supposed to be deprecated. Can I continue to use Meteor.sync()?