Hello Swapnil,

I am assuming that you are running a cloud version of the OS platform server and you are an enterprise customer. By default your domain name will be xxx-dev.outsystemsenterprise.com

Now you have changed the hostname to dev.mydomain.com  and none of the mobile application is working.

I would recommend the following steps.

1. Rename the host name back to xxx-dev.outsystemsenterprise.com

2. Service Center - > Factory - > Applciations ->  Your Application  -> Native Platforms - > Environment hostname  : Change  to dev.mydomain.com. Re generate the application.

3. Add a CNAME in the DNS setting of mydomain.com. i.e Hostname =  dev.mydomain.com and Canonical name = xxx-dev.outsystemsenterprise.com

This way both old application on the store( ipa , api ) and the new one will work. 

Once the application is approved by respective stores and downloaded by users rename the host name to dev.mydomain.com

Hello,

I realised that, with the above approach newly built mobile applications will not work due to issue in certificates. i.e new application will request https://dev.mydomain.com and from the server and the server will return certificate for xxx-dev.outsystemsenterprise.com and the mobile applications will not work due to difference in requested domain names. 

Here is another approach that will work.

1. Setup a NGINX Server
2. Setup this NGINX server to listen to dev.mydomain.com and install the certificates so that when you access https://dev.mydomain.com it will open the NGINX page with no certificate error.
3. Now configure the NGINX server to proxy all request to https://xxx-dev.outsystemsenterprise.com so that when you access https://dev.mydomain.com/ServiceCenter it should open the Service Center of xxx-dev.outsystemsenterprise.com 
4. Service Center - > Factory - > Applciations ->  Your Application  -> Native Platforms - > Environment hostname  : Change  to dev.mydomain.com. Re generate the application.

This should work - all the application with with the hostname  "dev.mydomain.com" will come to NGINX which in turn redirect to xxx-dev.outsystemsenterprise.com. Old apps will still goes to the xxx-dev.outsystemsenterprise.com. There will be no certificate related issues here.

Note : One should be familiar with NGINX configuration to make it work.

Hi Siya,

Thank you so much for your help.

It's totally working fine now.