Link between RQM and DOORS requirements are not reflecting after saving

We are using RQM 4.0.2 / DOORS 9.4.0.0/DWA1.5.0.0 and linking requirements from within RQM test plan or test case. No changes has been made to the configuration. Earlier linking was working but now when we link a requirement to a test case or test plan, save the changes and refresh the page, the link is not there in RQM. Looking into the "History" says the user has modified something but what is it, is not registered.

We are able to replicate the same behavior with RQM 4.0.3/ DOORS 9.4.0.0/DWA1.5.0.0.

The difference about our setup is that we are using a masking technique for the URLs. So if the RQM url is https://rqmserver:9443/qm, it has been provided a masked name as https://prodRQM/rqm

Same configuration is with DWA too. so the URL for DWA is https://prodDOORS/dwa instead of https://doorsserver:8443/dwa

However, to run the dbadmin command -dwaPort parameter has to be provided with some value as it can't take the null value. So we have used 443 port.

If we browse any of the above masked links with port 443 included in it, it redirects to the url (without port) and continues working.

Same configuration is with RQM 4.0.3 setup too. Kindly advice what we are missing as this is affecting our prod environment.