How to use the variable fractional delay in Simulink?

I'm having trouble using the variable fractional delay. I have a discrete sine wave going into the "Delay" port. I enabled sample time colors and verified that all my inputs to the delay block are discrete.

Despite this, I keep getting an error that says I should be using dsicrete time samples only. What could I be missing here?

I'm trying to build this but haven't been successful so far.

Thanks.

[Debraj]

I figured it out. MATLAB seems to pull up this error when there's a mismatch in the sampling rates of various sources in the design.

I set a common sampling rate of 25kHz(could be anything).

Under Simulink parameters, I made the step size fixed and changed the solver to discrete.

The model worked after that.