The Arizona vote was riddled with irregularities and should never have been certified. From David Robb at thebluestateconservative.com:

By now, most people have heard that the Arizona forensic audit of the 2020 election results is done. The results were presented in a public hearing last Friday, and the complete reports can be found here. Democrats and the MSM are happy because the audit showed that the total number of ballots counted generally matched the number reported, and the counted ballots showed that the totals for Biden and Trump effectively matched the numbers reported. They are asserting that despite what they claim was a partisan Republican audit conducted by rank amateurs it actually proved that Biden won and the election was fair and secure.
Republicans are happier, though, because the audit uncovered incontrovertible evidence of fraud and malfeasance in the election and in the conduct of those responsible for ensuring the integrity of the election. Although the totals generally matched the numbers that were certified. the audit found that there were huge quantities of ballots counted in the totals that should never have been included. For instance, 17,000 voters had two, three, and even four duplicate ballots counted, for a total of over 34,000 counted votes that should have been eliminated (page 62, here).
In several other cases, the stamp “Verified and Approved” appeared behind the pointer to the signature box on the return envelope (page 78). The problem, of course, is that the pointer was printed on the ballot envelope before the ballot was sent to the voter. How did the validation stamp get marked on the envelope before the pointer was printed?
Additionally, the audit showed that thousands more in-person ballots were counted than there were people who showed up to vote, thousands more mail-in ballots were received than were sent out, while thousands of votes were counted from voters who had moved and were no longer eligible. Altogether, there were numerous discrepancies in the ballot counting that make the total votes reported unreliable to a high degree. In other words, the number of votes affected by counting issues and potential election fraud exceeds the number of votes separating the candidates, such that it is impossible to tell who won the election in Maricopa County.