Welcome to the Community. Unfortunately in the CLOUD the option of setting up a custom domain is currently not available which you can configure your JSM portal out ot the box.
Here is a feature request that you can comment/track - https://jira.atlassian.com/browse/CLOUD-6999
Hope this helps.
Best, Joseph Chung Yin
Jira/JSM Functional Lead, Global Infrastructure Applications Team
For JSM June Challenge #2, share how your non-technical teams like HR, legal, marketing, finance, and beyond started using Jira Service Management! Tell us: Did they ask to start using it or...
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