Visualizing result of ParametricNDSolve

I want to solve and visualize system with a parameter using the following code:

L = 10
sol = ParametricNDSolve[{y'[t] == Sqrt[(k^4)/(y[t]^4) - 1], 
   y[0] == 0, Integrate[y[x]^(-2), {x, 0, L0}] == L/(k^2)}, {y[t], 
   k}, {t, 0, L0}, {L0}]
Manipulate[Plot[Evaluate[y[L0][t] /. sol], {t, 0, L}], {L0, 2, 3}]

However, I got an empty plot and no error or warning message. Why can it happen?
If there is no solution, should not there be an error message?

What is the value of k? Did you define it somewhere?

It should be defined from the second equation.

Integrate[y[x]^(-2), {x, 0, L0}] == L/(k^2)

On the other hand, it can be defined as y(L0), but with this expression it does not work either.

Well, I have Mma 7, it doesn’t know PrametricNDSolve. But may be you should give the Parameter explicitly according th the synthax

sol = ParametricNDSolve[{y'[t] == Sqrt[(k^4)/(y[t]^4) - 1],    y[0] == 0}, {y[t], k}, {t, 0, L0}, {L0,    k /. Flatten[
     Solve[Integrate[y[x]^(-2), {x, 0, L0}] == L/(k^2), k]]}]

But I can’t test ihat with my old version.

Unfortunately this does not work.
The error is: << expression for k >> cannot be used as a parameter.