Invalid short name when updating marketplace package

Steps to reproduce:

  1. I have build&exported; a new version of my package, which is already available at the marketplace.
  2. Use the UPDATE action in the content browser to attach the new file.
  3. Finally there is this error:

I have not changed anything
related to the company name. The one which is flagged as error now, worked the
last time. This is on SU10. How can I resolve this error?

Log out of your account and log back in. Worked for me, hope it works for you!

Thanks for your help! You mean, sign out my gamertag from the top right menu?
I tried that, then sign in again, then build&export; again and the upload is
still giving me the same error.

No log out of MCP and login again. Is a fault with MCP after re-logon you get
the new version of the portal. Best, Raul

Many thanks to both of you, @mngydg & @Simbol ! You both were right and after
doing the steps as described, it worked!