Failed to parse realm frontendUrl 'auth.mydomain.com'. Falling back to global value.: java.lang.IllegalArgumentException: The url [frontendUrl] is malformed #30317

nishit93-hub · 2024-06-11T05:07:53Z

nishit93-hub
Jun 11, 2024

Hi All,

I added a frontend URL "auth.mydomain.com" to have a realm on a different URL. since then I have been getting below error

ERROR [org.keycloak.quarkus.runtime.hostname.DefaultHostnameProvider] (executor-thread-118) Failed to parse realm frontendUrl 'auth.mydomain.com'. Falling back to global value.: java.lang.IllegalArgumentException: The url [frontendUrl] is malformed

JereSten · 2025-01-26T10:13:01Z

JereSten
Jan 26, 2025

Hi,
i have the same issue

3 replies

shawkins Jan 26, 2025
Collaborator

Please try your scenario with a newer version of Keycloak using hostname v2. If the still see an exception please provide all hostname related configuration, and we can determine if there is an actual issue here.

addis144 Feb 17, 2026

I can confirm this is still happening in 26.5.2

root@dev-server11 dev11]# journalctl -f -n1000 -u keycloak |grep Hostname
Feb 17 12:13:34 dev-server11.com kc-wrapper.sh[103823]:         at org.keycloak.url.HostnameV2Provider.lambda$getRealmFrontUriBuilder$4(HostnameV2Provider.java:135)
Feb 17 12:13:34 dev-server11.com kc-wrapper.sh[103823]:         at org.keycloak.url.HostnameV2Provider.getRealmFrontUriBuilder(HostnameV2Provider.java:132)
Feb 17 12:13:34 dev-server11.com kc-wrapper.sh[103823]:         at org.keycloak.url.HostnameV2Provider.getFrontUriBuilder(HostnameV2Provider.java:108)
Feb 17 12:13:34 dev-server11.com kc-wrapper.sh[103823]:         at org.keycloak.url.HostnameV2Provider.getBaseUri(HostnameV2Provider.java:76)
Feb 17 12:13:34 dev-server11.com kc-wrapper.sh[103823]: 2026-02-17 12:13:34,677 ERROR [org.keycloak.url.HostnameV2Provider] (executor-thread-23) Failed to parse realm frontendUrl '*'. Falling back to global value.: java.lang.IllegalArgumentException: The url [Realm frontendUrl] is malformed
Feb 17 12:13:34 dev-server11.com kc-wrapper.sh[103823]:         at org.keycloak.url.HostnameV2Provider.lambda$getRealmFrontUriBuilder$4(HostnameV2Provider.java:135)
Feb 17 12:13:34 dev-server11.com kc-wrapper.sh[103823]:         at org.keycloak.url.HostnameV2Provider.getRealmFrontUriBuilder(HostnameV2Provider.java:132)
Feb 17 12:13:34 dev-server11.com kc-wrapper.sh[103823]:         at org.keycloak.url.HostnameV2Provider.getFrontUriBuilder(HostnameV2Provider.java:108)
Feb 17 12:13:34 dev-server11.com kc-wrapper.sh[103823]:         at org.keycloak.url.HostnameV2Provider.getBaseUri(HostnameV2Provider.java:76)
Feb 17 12:13:41 dev-server11.com kc-wrapper.sh[103823]: 2026-02-17 12:13:41,432 ERROR [org.keycloak.url.HostnameV2Provider] (executor-thread-23) Failed to parse realm frontendUrl '*'. Falling back to global value.: java.lang.IllegalArgumentException: The url [Realm frontendUrl] is malformed

shawkins Feb 17, 2026
Collaborator

The frontendUrl set on a realm is expected to be a full URL - it cannot be * and needs to include the protocol e.g. https://auth.mydomain.com

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Failed to parse realm frontendUrl 'auth.mydomain.com'. Falling back to global value.: java.lang.IllegalArgumentException: The url [frontendUrl] is malformed #30317

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Failed to parse realm frontendUrl 'auth.mydomain.com'. Falling back to global value.: java.lang.IllegalArgumentException: The url [frontendUrl] is malformed #30317

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nishit93-hub Jun 11, 2024

Replies: 1 comment · 3 replies

Uh oh!

JereSten Jan 26, 2025

Uh oh!

shawkins Jan 26, 2025 Collaborator

Uh oh!

addis144 Feb 17, 2026

Uh oh!

shawkins Feb 17, 2026 Collaborator

nishit93-hub
Jun 11, 2024

Replies: 1 comment 3 replies

JereSten
Jan 26, 2025

shawkins Jan 26, 2025
Collaborator

shawkins Feb 17, 2026
Collaborator