  We extend the framework of a posteriori error estimation by preconditioning
in [Li, Y., Zikatanov, L.: Computers \& Mathematics with Applications.
\textbf{91}, 192-201 (2021)] and derive new a posteriori error estimates for
H(curl)-elliptic two-phase interface problems. The proposed error estimator
provides two-sided bounds for the discretization error and is robust with
respect to coefficient variation under mild assumptions. For H(curl) problems
with constant coefficients, the performance of this estimator is numerically
compared with the one analyzed in [Sch\"oberl, J.: Math.~Comp.
\textbf{77}(262), 633-649 (2008)].
