An SSL Certificate cannot be issued: Could not issue a Let's Encrypt SSL/TLS

[senthil]

Symptoms
1. Attempting to issue an SSL Certificate via Domains>example.com>SSL/TLS Certificates>install Let's Encrypt
Certificate results in the following error:

Could not issue an SSL/TLS certificate for example. com
Details
Could not issue a Let's Encrypt SSL/TLS certificate for example. com.

2. The following errors can be found in %plesk_dir%admin\logs\php_error.log:

Code Select Expand

[2025-04-24 14:41:42] 11668:680a07530e8bc DEBUG [extension/letsencrypt] pm_Exception:
Unable to execute command extension: proc_open(): Command conversion failed
file: C:\Program Files (x86)\Plesk\admin\plib\pm\ApiCli.php
line: 269 code:
0 trace:
#0 C:\Program Files (x86)\Plesk\admin\plib\pm\ApiCli.php(60):
pm_ApiCli::execSimple(string 'extension',string '"C:\Program Files
(x86)\Plesk\bin\extension.exe"  --call sslit --common-challenge-dir -info -format
...', integer '1', array, string '')
#1 C:\Program Files
(x86)\Plesk\admin\plib\modules\letsencrypt\library\PleskCli\PleskCliService.php(23):
pm_ApiCli::call(string 'extension', array, integer '1')
#2 C:\Program Files
(x86)\Plesk\admin\plib\modules\letsencrypt\library\Environment\CommonChallengeDir.php(73):
PleskExt\Letsencrypt\PleskCli\PleskCliService->call(string 'extension', array)
3. The folder C:\Windows\System32 is missing from the Path System environment variable.

Cause

The C:\Program Files (x86)\Plesk\admin\plib\pm\ApiCli.php utility cannot open a process since PathSystem
Environment Variable is missing C:\Windows\System32, which results in failure to issue an SSL Certificate.

Resolution

To add the System Environment Variable, do the following:

• Press Win + R, type sysdm.cpl, and press Enter.
• Go to the Advanced tab.
• Click Environment Variables.
• Under System variables, find and select Path, then click Edit.
• Click New and add: C:\Windows\System32
• Reboot the server to apply the changes.