Symptoms
-
Unable to apply the Plesk license to the server
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The following message is shown in Plesk UI when trying to upload a license key file:
PLESK_INFO: 502 Bad gateway
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The following messages are present in
/var/log/sw-cp-server/error_log
:[error] 20770#0: *272 recv() failed (104: Connection reset by peer) while reading response header from upstream, client: 91.204.25.4, server: , request: "POST /server/key_upload.php HTTP/1.1", upstream: fastcgi://unix:/var/run/sw-engine.sock:", host: "52.53.62.41:8443", referrer: "https://52.53.62.41:8443/server/key_upload.php"
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The following messages are present in
/var/log/sw-cp-server/sw-engine.log
:WARNING: [pool plesk] child 2268 exited with code 127 after 11.528033 seconds from start
NOTICE: [pool plesk] child 2283 started
Cause
The opcache
 module is not disabled for Plesk engine service (sw-engine).
Resolution
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Connect to the server via SSH
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Edit the file
/usr/local/psa/admin/conf/php.ini
with text editor. Make sure that opcache is disabled. The relevant line should look like:opcache.enabled = 0
-
Restart sw-cp-server and sw-engine:
# service sw-cp-server restart
# service sw-engine restart