Thanks Immortal Bikram.
I think there is bug in webmaster tool itself. I tried the same step before but it didn’t worked. Now when I tried it started working.
If any other facing similar issue, just resubmit your sitemap by removing, and refreshing that page. sometimes it may shows the same error. If it once again shows the same error do as..
1. select the sitemap which is showing error and click on resubmit button.
If it shows the same error, remove that sitemap and submit it again. Continue the similar process util you get success message.
By using this method I’m submitting all my sites now which is showing error. And it is working for me.
Hope it helps other users as well.
Regards,
Arun P.K
Income Days-My Journey with Online Income