Is anyone having trouble entering serial number for $60 sig store coupon for buying new p320 or p365 in there website?

Anytime I have trouble entering something on a website I try a different browser. I try MS Edge over my Firefox.
This may not be your case but I thought I would throw it out there.

Had no problem with my coupon. I use the Chrome browser.

I keep getting invalid serial number

Call SIG costumer service. I had trouble registering a Legion (twice), and they straightened it out while I was on the phone with them.

I submitted mine last night, no issues and I got the email with the coupon code this morning.