Updated SSL cert expiration date not refreshing

I recently renewed some SSL certs for our domain.  Xymon was testing the https addresses and was correctly showing the ciphers and expiration date.  But after I renewed and applied the certs to our servers Xymon still shows the old expiration date on one of our IIS servers, not the new date.  The issue is only appearing when Xymon tests our IIS server, not a different Linux server which shows the correct updated date.  The SSL certs were applied correctly to the IIS server and all browsers and external tests show accurate dates, but not Xymon.  Any idea why this would occur?  IIS server is running IIS 8.5

Thanks.
Kris Springer