Inseminating too soon?

I have had two failed iui's using frozen sperm. We were told that once we had a positive opk to come in for insemination. I've seen so many posts about ovulation occurring up to 36hrs after peak and frozen sperm only lasting 12-24 hours...if we are inseminating the same day as peak is that too soon? Is our sperm dieing before I ovulate? We are preparing for our next round and I am wondering if we should inseminate the day after peak? I dont know how many more rounds we can do. I appreciate any insight. Thank you