Adding conditions to dsolve makes it unsolvable

I am trying to use "dsolve" to solve a differential equation system with three variables and five constants, but I am getting an error when I add a third condition.

Error:

"Unable to reduce to square system because of the number equations differs from the number of indeterminates."

Answer 1

[MathWorks Support Team]

This error is indicating the this problem is unsolvable with the given information. To solve the system of differential equations with all these conditions, you need to include more information on one of the variables. One of the variables is missing either a differential equation, a function or actual values. One of these is required in order to solve these equations for the desired constants.