This error message typically appears in COMSOL Multiphysics when the software is unable to compute the solution for a dependent variable.
There could be several reasons why the solution is not computed. For example, it could be due to an incorrect boundary condition or meshing settings, or it could be due to a convergence issue in the solver.
To troubleshoot this issue, you can try the following steps:
1. Double-check your boundary conditions and make sure they are correctly specified.
2. Check your mesh settings and make sure they are appropriate for the problem you are trying to solve.
3. Try changing the solver settings, such as the maximum number of iterations or the convergence tolerance, to see if that resolves the issue.
4. If none of the above steps work, try restarting COMSOL and running the simulation again.
If the issue persists, you may need to contact COMSOL technical support for further assistance. They can help you diagnose the problem and provide specific solutions based on the details of your simulation.