Why was Jennie Garth not at Tiffani Thiessen's wedding?

Answer 1

She was there Tiffani Amber Thiessen and husband Brady Smith's wedding rehearsal dinner was held at the rooftop venue El Cielo, with guests who included former cast mates from 90210, Tori Spelling, Jason Priestly and Jennie Garth. http://www.santabarbaraca.com/articles/index.cfm?action=View&ArticleID=35

Answer 2

Beacuse Tiffani stole Jennie's boyfriend, and made a sex tape and sent it to jennie. Then they hashed out their differences and were friends again then one day they went to lunch at Miko's and got in a huge fight about who is prettier and has the better body, that ended in a jello fight which Jennie won. So after all that Tiffani being even more angry pooped in a bag and lit it on fire and put it on Jennies doorstep and rang the bell, well Jennie came out and stomped the fire out and got poo on her foot.