Although this shouldn't really be an issue if you were able to successful approve order before, is the WHMCS install on the same server as the Freeradius install (because of localhost)? Also is there still open slots in the database? (As set under the "Servers" section under "Setup" in WHMCS)
If its never happened before and its a one time issue, I would just enter that customers details into the Freeradius database manually. If this issue happens again in the future then maybe something is actually wrong.
When making a recurring promotion,
After selecting "Enable" and entering the "Recur for x times," does the number of times include the first time?
In other words, if I have a promotion for a discount on a monthly subscription and I wish for the promotion to discount for 3 successive months, should I enter 2 or 3 for the recurring number of times? Thanks!