SRA moved all of the data to the cloud per https://ncbiinsights.ncbi.nlm.nih.gov/2020/02/24/sra-cloud/
You can still download data for free using sratoolkit as described in the official documentation here: https://www.ncbi.nlm.nih.gov/sra/docs/sradownload/
For documentation on how to download data from the cloud, see https://www.ncbi.nlm.nih.gov/sra/docs/sra-aws-download/