Password Reset Link contains invalid characters

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Summary
The URL sent in password reset emails contains invalid characters.

Steps to reproduce
Password reset flow

Expected behavior
Receive password reset link:

https://MYDOMAIN.org/reset_password_complete?token=TOKENINFO

Observed behavior
Received password link:

https://%5CMYDOMAIN.org/reset_password_complete?token=TOKENINFO

Hi @barnops and welcome to the Mattermost forums!

Can you confirm that the value for your SiteUrl (either in config.json or in the environment variable MM_SERVICESETTINGS_SITEURL in your .env file if you’re using docker) does not contain this character in the domainname? %5C is the ascii hex code for a \ character, please have a look at your settings.