Unable to refresh license online

Symptoms

You can't refresh the license in SCCM Console. Error "License refresh failed: Could not establish connection to pmm.parallels.com" is thrown:

The following errors are observed in pma_isv_proxy_service.log:

12-18 09:28:02.087 W /LicenseSvc:4308:12bc/ SSL errors:
    SSL error 11 (The issuer certificate of a locally looked up certificate could not be found)
        Subject: USERTrust RSA Certification Authority
        SHA1: eab040689a0d805b5d6fd654fc168cff00b78be3
        Issuer: AddTrust External CA Root
12-18 09:28:02.088 W /LicenseSvc:4308:12bc/ Backend request failed: 6 (SSL handshake failed)
12-18 09:28:02.088 I /LicenseManager:4308:12bc/ License refresh finished with 8 (Error communicating with license service)
12-18 09:28:02.089 D /pma_isv_proxy_service:4308:12bc/ License manager replied with 8 (Error communicating with license service)
12-18 09:30:10.033 W /LicenseSvc:4308:12bc/ SSL errors:
    SSL error 11 (The issuer certificate of a locally looked up certificate could not be found)
        Subject: USERTrust RSA Certification Authority
        SHA1: eab040689a0d805b5d6fd654fc168cff00b78be3
        Issuer: AddTrust External CA Root
12-18 09:30:10.036 W /LicenseSvc:4308:12bc/ Backend request failed: 6 (SSL handshake failed)
12-18 09:30:10.036 W /LicenseManager:4308:12bc/ Usage report finished with 8 (Error communicating with license service)

Cause

The exact cause is unknown.

Resolution

Reconfigure PMM Proxy and refresh the license.

Errors related to Mac Agent will be gone, too.