Read more on OS reinstalling from ISO here (for virtual servers) and here (for dedicated servers).
Can't upload ISO in the panel
Check name of the file you're uploading - you should use only lowercase letters in the file extension. So, it should be «.iso», not «.ISO». Also, use only letters and numbers.
Error in DCI manager
Error occurred when mounting ISO-image on the IPMI proxy server. Script output: ''
Try to delete ISO from the panel and upload it one more time.
If you're still experiencing issues, contact us via chat or ticket from control panel.