Thank you for the post.
I apologize for the delay. I have also responded to your similar report here:
If the plugins are not being seen in the FileMaker Server 13 Admin Console, are you able to see the plugins after a restart?
If the plugin is seen by the FileMaker Server 13 Admin Console, but unable to be enabled, contact the developer of the plugin to confirm compatibility with FileMaker Server 13.
Having same problem, plugin not displaying at all even after a restart of the the FM Server. Note the plugin I am using PO3it may not be compatible yet, but I did think it would display.
Thank you for the reply.
I am unfamiliar with that particular plugin or whether the developer updated the plugin for FileMaker Server 13. Contact the third party plugin developer for more specific information about that plugin.
Additionally, here are some useful resources related to installing and updating plugins:
I was having the same issue with a few plugins including the scriptmaster plugin. I ensured that all were 64-bit plugins and were in the extensions folder. I signed out and back in with no luck.
I decided to run fmsadmin restart fmse from the command line and instantly they appeared in the plugins list under the admin console. Hopefully it will work for you as well.