String corrections to circular Wilson loop and anomalies

We study string quantum corrections to the ratio of latitude and circular Wilson loops in $N=4$ super-Yang-Mills theory at strong coupling. Conformal gauge for the corresponding minimal surface in ${AdS}_5\times S^5$ is singular and we show that an IR anomaly associated with the divergence in the conformal factor removes previously reported discrepancy with the exact field-theory result. We also carefully check conformal anomaly cancellation and recalculate fluctuation determinants by directly evaluting phaseshifts for all the fluctuation modes.