Can not upload file to sharepoint 2019 - error storebusyretrylater

Hello people. I wanted to ask what can be the problem that i can not upload a file to a particular sharepoint site. I get an error storebusyretrylater tag=0x121d3da, but when i try to upload on another site the upload is successful.. I can't figure what is the problem that just on one of the portal sites it won't upload a single file.. I checked the space and freed 20gb but the problem persists. I read something that the size quota may be the problem but i can not find an option to change it. Where do i find this option or is there any other solution to this problem? Here is a screenshot of the problem

Thank very much