This error occurs when the python installation does not have the requests library as listed in the SeaDAS Requirements.  If you are using linux and are allowed to install packages there should be a python[N]-requests package.  Some linux distributions as well as macOS may provide limited use python configurations intended only for system management scripts.   If you are using a "limited use" python installation (consult your OS documentation) you should consider installing a different Python system such as Anaconda (supports linux and macOS).  If you encounter problems installing the requests library please include your OS and Python version details so other users using the same OS may be able to suggest a solution that worked for them.