Unable To Edit Payment On One Specific Order

I've been trying to update payment info on an order which I received payment for and it just keeps "thinking" and doesn't bring me the pop-up box or do anything. I've been able to go back into old orders and edit payment so it seems specific to this particular order. Ideas? (using current Sytist version, in fact I just updated it today in case that was the issue and it's apparently not)

Sounds like mod security is being triggered for some reason. Mod security is good but also has false positives. 

Or possibly a javascript error. 

If it is mod security your host will need to whitelist the rule it is trigging.

• 1) The link / URL to your Sytist admin (where you log into your Sytist admin).
• 2) The admin username and password (or create me an admin account by clicking Admins in the upper right corner of the admin pages).
• 3) The order number.