Check your source feed that Feedburner is pointing at - if it is ove 512 kb in size feedburner will stop updating.
It is a "feature" of feedburner - source feeds can not be greater than 512 kb in size - and no - there is no error message from feedburner when this happens - simply it just stops updating.
One thing you could do if Podbean allows it - is to limit your feed to the last 100 episodes - or if they have the option - strip out all the HTML code from the source feed - that last option really reduces the size of the source feed allowing all your older episodes to stay live. Not sure if Podbean has that option however.
Rob W
libsyn