Notes/Domino 6 and 7 Forum : SSL Keyfile/stash problem

I am having a problem with my Domino servers running SSL. I frequently get pages (or their elements) not returned when using https. Refreshing the page a number of times eventually brings it up, but that's not really a solution.

I've tried using the SSL debugging options in notes.ini and find the following:

ReadKeyfile> Recovering password from stash file
ReadKeyfile> Password is <password>
ReadKeyfile> Reading keyfile /my1keyfile.kyr
ReadKeyfile> Looking for trusted roots
....
....blah blah blah
....
ReadKeyfile> Recovering password from stash file
ReadKeyfile> Password is
ReadKeyfile> Reading keyfile /my1keyfile.kyr
ReadKeyfile> Read failed: bad password

So it looks like, for some reason, it is failing to read the password from the stash file. This only seems to happen when the server is in use by other users (who are not using SSL, just http) - when it's just me connected to the machine, https works fine all day!

I have looked at the load on the server and can't see any problems. Lots of free http threads, processor etc.