If this occurs, the problem should have been recorded in your artifactory.log file. To resolve this issue, you'll need to manually correct and bootstrap a config descriptor from your file system. Locate the $ART_HOME/etc/artifactory.config.latest.xml file, it will likely be the old XML version, which is ok:
Thereafter, fix the XML syntax, attempt to bootstrap the file by renaming it to $ART_HOME/etc/artifactory.config.import.xml, and restart Artifactory
[Expected log entries during a config bootstrap] 2019-09-10 23:04:44,973 [art-init] [INFO ] (o.a.d.r.CentralConfigReader:92) - The current Artifactory config schema namespace is 'http://artifactory.jfrog.org/xsd/2.2.3' The provided config does not seem to be compliant with it. 2019-09-10 23:04:45,026 [art-init] [INFO ] (o.a.d.r.CentralConfigReader:71) - Converting artifactory.config.xml version from 'v222' to 'v223'
Thereafter, fix the XML syntax, attempt to bootstrap the file by renaming it to $ART_HOME/etc/artifactory.config.import.xml, and restart Artifactory