We are working on OJS 2.3.4 since 2011 with no problem. One instance has 5 journals hosted in Ubuntu 10.04LTS. Now we are facing difficulty in uploading the files of bigger sizes in step 2 & step 4 of article submission steps. Since beginning php.ini has maximum file size setting of 20M (max_upload_size = 20MB, post_max_size = 40 MB) and it was working fine. Even the authors were able to upload file size of >10MB. But recently, we are unable to upload even the file size of 1Mb. When we upload a file of size greater than 600 kb, sometimes, we get Error 324 (net::ERR_EMPTY_RESPONSE). While uploading the file of bigger size, sometimes, it goes back to step 1 or simply shows blank screen, even it tries uploading for 30 min with no success. We tried uploading from Chrome, Firefox & IE. Using Chrome, we are able to upload file of maximum size 1MB but on IE & Firefox it accepts much less (600-800Kb). We tried to find the solution on technical forum but could not succeed. Any technical help would be greatly appreciated.