68553: Acronis Cyber Protect Cloud: Activity fails with "Failed to establish connection with cloud storage. Could not perform SSL_write() call"

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Last update: 29-04-2021


Backup to Cloud storage fails with:

Failed to establish connection with cloud storage

Could not perform SSL_write() call


The error is usually caused by connectivity issues with Cloud storage.


  1. Download Cloud Connection Verification Tool and use it to identify possible network issues, such as closed ports.
  2. Some firewall software may block the data upload even when the required ports are open. Check the firewall configuration and make sure upload to Acronis datacenters is not blocked. Access ports and hostnames for Acronis datacenters are listed here: Acronis Cyber Cloud: access ports and hostnames
  3. To identify possible issues with certificates in the connection chain, proceed as described in Using OpenSSL to troubleshoot connection issues caused by firewalls and DPI software

Collect information

If suggested steps did not help to resolve the issue, collect information for further investigation and contact Acronis Customer Central:

  1. Acronis Cloud Certificate and output of Cloud Connection Verification Tool.
  2. Acronis system information from the affected agent machine: see Acronis Cyber Protect Cloud: Collecting system report
  3. OpenSSL output.