Tax not working and check not working for the state of California (state we have formated for tax

I added Sales Tax to our MarketPress plugin and now we can’t checkout if the state is California (same state as the tax state). Why is this? Also I tried checking out in Wisconsin and it did not charge me the California tax rate that I have in MarketPress. I believe it should… Right? Please help ASAP.

Please test with address:

1027 185th Ave

Balsam Lake, WI 54810 (state) Wisconsin and can also put in state = California for testing.

Thank you,

Julie