Well in that case, you can update the theme manually instead. Please check out "Manual Updates" section from this knowledge base article: https://theme.co/apex/forum/t/setup-updating-your-themes-and-plugins/62
You can also do the following:
- Go to X > Validation > Theme Options Manager and download the XCS file to your local machine.
- Go to Appearance > Themes and switch the theme to Twenty Seventeen theme.
- Delete X theme completely.
- Go to your dashboard (https://theme.co/apex/dashboard) and download a fresh copy of the X theme (x.zip)
- Go back to Appearance > Themes and add a new theme by selecting to upload the x.zip file. Once uploaded, please activate it.
- When you see that the X theme is installed, please go to X > Validation > Theme Options Manager and import the XCS file which you have downloaded. This would make sure that you have preserve the same theme options settings as you have it before.
- And lastly, you can initiate to validate the theme again.
Hope this helps. Please let us know how it goes.