There are many issues with WU. Yours happens to be one of them.
At this time there isn't a fix unless WU issues one.
Your options are limited with where you can send data with WL.
As an alternative you could use Cumulus software which has more options to send your data over the internet. It's donationware software and is very stable.
The options are PWS, CWOP,Weatherbug, and WOW.
Good luck.