Institutions typically use different ways (Shibboleth, LDAP, etc.) to authenticate users. It is difficult to achieve a one-size-fits-all deployment to address all the different authentication is done in OLE. This bottleneck can be cleared by using a reverse proxy.
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If you are experiencing HTTP 501 ("Method Not Implemented") errors, this may be the cause. Check your Apache version and error logs for messages such as "ajp_marshal_into_msgb - No such method PATCH".
Possible
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Fixes
2. Use at least Apache 2.4.4 with mod_proxy_ajp.
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