I am trying to upload data in a simple form but it keeps not uploading. Could the issue be related with size of images or video?
Possibly yes. Form attachments are limited to max 10MB for each file (and 100MB total per submission) so please check that any attached images, video or audio files are under this.
In the case of images, you may wish to consider adding a max-pixels value against any image questions to automatically reduce the size of photos.
