Sectigo, one of the SSL Certificate Authorities had their root SSL certificate expire at the end of May 2020 leaving Windows XP and Windows Server 2003 machines unable to trust issued SSL certificates. To resolve this issue simply export the updated root Sectigo SSL certificate from a newer operating system which automatically updates SSL Certificate Authorities (CAs), transfer the exported certificate to the affected Windows XP or Windows Server 2003 machines and then import it into the "Trusted Root Certificate Authorities" store on the local machine account.
On your workstation, open the start menu, click on Run, type in: 'mmc' and press the OK button.
From the top menu, select File - Add/Remove Snap-in
In the Add or Remove Snap-ins dialog, click on 'Certificates', click on Add> and then select the Computer account -> Local computer-> Finish.
Press OK and expand up to the 'Trusted Root Certification Authority' click on 'Certificates' inner node to see the list of certificate authorities stored on the computer.
Identify the Sectigo root SSL certificate named "AAA Certificate Services", right-click on it, and from the All Tasks section click on the Export context menu entry.
From the dialog that opens, select the Base 64 format, give it a destination path and confirm.
On the affected Windows XP and Windows Server 2003 machines, copy the exported certificate file.
Open mmc -> add snap-in -> add certificates to the local computer account. Right click on the "Trusted Root Certification Authorities" node, select all tasks -> Import and select the exported certificate file.
Restart the Pulseway service and the Pulseway Manager if opened and the connection should go through.