After you click Analyze tab 
Structural Analysis panel 
Analyze in Cloud, the application starts preparing a model for structural analysis. It extracts the analytical model from the project, checks if the analytical model has already been uploaded to the cloud, verifies and then uploads the model. Verification of the model before it is uploaded checks if it is correct from the viewpoint of structural analysis. In this way it ensures that the model being analyzed is correct and the analysis results are reliable. It also prevents uploading models with errors to the website; if errors are detected, the analysis is disabled. You need to fix them to allow the analysis to proceed.
Errors of an analytical model disabling the structural analysis
- Errors concerning material:
- A material is not assigned to the element
- A structural material is not assigned to the element
- A value of the Poisson's ratio for the material is incorrect
- A value of the Young modulus for the material is incorrect.
- Errors concerning linear members
- Section properties are not assigned to the element
- An incorrect section is assigned to the bar
- Parts of Beams or Columns overlap.
- Errors concerning planar objects
- Section properties are not assigned to the slab or to the wall
- The slab or wall thickness is zero.
- Errors concerning supports
- A part of the model is not supported
- The model is not supported.
- Errors concerning loads
- Load Cases are not defined.
If warnings occur, you can still send the model for analysis ignoring them. Or you can view them, fix the model, and then restart the analysis.