# MainNet validator crashing after onboarding

**URL:** <https://forum.canton.network/t/mainnet-validator-crashing-after-onboarding/8551>\
**Category:** App Development\
**Created:** [April 21, 2026, 1:10pm UTC](https://forum.canton.network/t/mainnet-validator-crashing-after-onboarding/8551 "2026-04-21T13:10:59Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Nikita\_Yakubovich](https://yyz2.discourse-cdn.com/flex034/user_avatar/forum.canton.network/nikita_yakubovich/32/7559_2.png) [@Nikita\_Yakubovich](https://forum.canton.network/u/Nikita_Yakubovich)\
**Post date:** [April 21, 2026, 1:10pm UTC](https://forum.canton.network/t/mainnet-validator-crashing-after-onboarding/8551/1 "2026-04-21T13:10:59Z")

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Hi team, trying to onboard a MainNet validator at IP `178.104.105.128` and hitting the same wall with clean installs of both 0.5.17 and 0.5.18. On 0.5.18 the validator container can’t even reach the participant container, just connection refused on port 5002, so onboarding never starts. On 0.5.17 it actually connects and finishes onboarding with the success message, but then immediately crashes with `UNIMPLEMENTED: Method not found: ReconnectSynchronizer`. Volumes wiped between attempts, migration ID set to 4, sponsor and scan URLs are the standard sync.global ones. Any pointers on which version is actually stable for MainNet right now, or if there’s a known workaround? Thanks.

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**Author:** ![Kenny](https://avatars.discourse-cdn.com/v4/letter/k/90db22/32.png) [@Kenny](https://forum.canton.network/u/Kenny)\
**Post date:** [April 23, 2026, 1:51pm UTC](https://forum.canton.network/t/mainnet-validator-crashing-after-onboarding/8551/2 "2026-04-23T13:51:45Z")

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I’m also experiencing a related issue. It seems like it’s trying to reconnect or initialize the participant, but it’s not succeeding.

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**Author:** ![lesnik\_UTSA](https://yyz2.discourse-cdn.com/flex034/user_avatar/forum.canton.network/lesnik_utsa/32/7568_2.png) [@lesnik\_UTSA](https://forum.canton.network/u/lesnik_UTSA)\
**Post date:** [April 24, 2026, 6:21am UTC](https://forum.canton.network/t/mainnet-validator-crashing-after-onboarding/8551/3 "2026-04-24T06:21:53Z")

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I also couldn’t connect with version 0.5.18, but after switching to version 0.5.17 the node started working.