Unable to Convert Caffe SSD300 Model to Intermediate Representation (IR)

Received error when converting SSD300 model to IR:

[ FRAMEWORK ERROR ] Model Optimizer is not able to parse <Some Dir>/OpenVINO/inference-engine/samples/hello_reshape_ssd/./public/ssd300/models/VGGNet/VOC0712Plus/SSD_300x300_ft/VGG_VOC0712Plus_SSD_300x300_ft_iter_160000.prototxt

1. Install Python* 3.8 on the system
2. Run the mo_caffe.py command:

   python3 mo_caffee.py --input_model /<Download_Dir>/deployment_tools/open_model_zoo/tools/downloader/public/ssd300/models/VGGNet/VOC0712Plus/SSD_300x300_ft/VGG_VOC0712Plus_SSD_300x300_ft_iter_160000.caffemodel --input_proto /<Download_Dir>/deployment_tools/open_model_zoo/tools/downloader/public/ssd300/models/VGGNet/VOC0712Plus/deploy.prototxt/

• Operating Systems for OpenVINO 2021.3: Ubuntu 18.04, Ubuntu 20.04
• Default Python version for Ubuntu 18.04 : Python 3.6.
• Default Python version for Ubuntu 20.04 : Python 3.8.