I got the same problem, on thursday when I installed wlm 9 with my @hotmail.com account. Now wlm doesn't refresh the mail anymore. I went back to wlm 8.5 and it's still not working. I tried my account on different computer using wlm 8.5 and I can say that the result was the same.
I also tried wlm 8.5 with my other account @hotmail.fr and on this one the refresh works.
Maybe wlm 9 did modify something on the live server, maybe it's a server problem ? I don't know.
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