How to handle MeteorException?

[BeayemX]

When I try to execute a meteor method by calling yield return (Coroutine)methodCall; I get the following exception Internal server error.

This error occurs only sporadically even though the parameters are correct. When I look into the database everything gets transmitted correctly. Just the lines after yield won't be executed due to the error.

Meteor calls have to be called in a coroutine but I can't use a try-catch-block around a yield call.

The documentation does not help either. So how do you handle a MeteorException?

Edit:
It was difficult tracking the problem down but I could find the reason for the Internal server error. But the question still applies, how does one handle MeteorExceptions? For example when trying to login with a wrong username a MeteorException gets thrown. After this execption, meteor seems to be broken and I can't login even if I use the correct credentials afterwards.