You may notice that the site server communication profile contains port 4726 in the HTTPS communication hosts entry section. For example 871ss.example.com:443;871ss:443;871ss.example.com:4726;871ss:4726
ITMS 8. x
Known Issue
This is a known defect in the product and fixed in our ITMS 8.7.3 .
Workaround:
In the meantime having port 4726 is not necessarily bad. It may cause some confusion for endpoints but they will work it out and fall back to 443. You can remove the entries for 4726 if you wish.