Can't Upload Images/Thumbnail Images Missing from Index Page

Hi, I hope you are all doing well. I need help with my site. I noticed today that all the thumbnail images on my home page were missing replaced by a little red x and the image name. You can view the image in the full post. Than I noticed that I could not upload images. To see my site and the missing images go to: https://onlinebusinesssystems-diyim.com. I have tried everything from checking permissions to the upload folder to deactivating all plugins. Can somebody help? ??

Thank you
Tony S