HTTPS access for mobile client

Please assist on access using mobile client over https connections

platform hostname is erp.mydomain.com which accessed normally by browsing https://erp.mydomain.com

Server address for mobile app does not respond with any of the following
https://erp.mydomain.com
erp.mydomain.com:433

Please advice

did you tried erp.mydomain.com

it works with custom port say erp.mydomain.com:64942 as HTTP
but once i moved to HTTPS, does not connect

Did u doble check if ssl port open in the firewall? Can u reach other ssl servers from mobile connection?

yes, it is opened, and the platform is already accessible via https://erp.mydomain.com

Can u test from mobile connection:

telnet erp.mydomain.com 433

And share results?