After trying to figure out what is causing the One-Click Postage to not work for some users while it continues to work for others (including me), I’ve discovered a few things:

• There was a bug on One-Click Postage that sometimes would not send the “data-form-key”, that’s been fixed and hopefully will fix most of the cases. This usually happened when you tried to reblog your own posts.
  
  
• Tumblr returns an invalid JSON object sometimes, not sure why but it has happened 2 times while I was extensively trying it out.
  
  
• Tumblr rejects reblog requests when you try to reblog the same post 2-3 times. Not sure why, probably another limitation put in place to stop spamming or something.
  
  
• On some versions of Safari, you don’t get automatic updates. Not sure what is causing it, and will release a new version of XKit for Safari soon.
  
  
• I’ve fixed a bug that would sometimes cause “undefined” to appear on captions while using “Append Caption” feature.

So anyways, I’ve released another new version of One-Click Postage. Please upgrade to it and let me know if the problems still continue.

In this version I’ve added some debugging stuff too so sending me your log from www.tumblr.com/xkit_log will help me figure out what is wrong with it.

Thank you.