How to take Time Measurements using LT Spice
You labeled the nodes Vin and Vout, and you are using the output node correctly (V(Vout)), but not the input node ((Vin) instead of V(Vin)).

You also forgot the asterisk for multiplication: 0.63*V(Vin). If you need to be more precise, use (1-exp(-1))*V(Vin), impose a small timestep (1m of total time, or less), and, optional, add .opt plotwinsize=0 to disable waveform compression. It doesn't look like you need it, though.

Finally, you use cross=5 but you only have four rise/fall edges. Instead, use rise=1 for the first rising edge, rise=2 for the 2nd, etc. You don't need td here.

The new command should look like this:

.meas TRAN res1 FIND time WHEN V(Vout)=(1-exp(-1))*V(Vin) RISE=1


As a minor addition, you could use a bit sharper rise/fall edges on your source, to avoid wrong readings. 1u would do just fine, without sacrificing decimals.

A little bit of attention can go a long way. This also implies no haste.