Links working fine on this side.
Replicated the problem. Found it was described in another thread (probably librabbitmq merged packages on centos repo) and the dependency fixed in this onlyoffice issue (package no longer required by onlyoffice).
Updated mrmarkuz repo on my test server. Then:
[root@server ~]# rpm -q --whatrequires librabbitmq-tools
onlyoffice-documentserver-5.1.1-23.x86_64
[root@server ~]# yum -y install https://github.com/ONLYOFFICE/DocumentServer/releases/download/ONLYOFFICE-DocumentServer-5.1.4/onlyoffice-documentserver.x86_64.rpm
[root@server ~]# rpm -q --whatrequires librabbitmq-tools
no package requires librabbitmq-tools
[root@server ~]# yum remove librabbitmq-tools
[root@server ~]# signal-event nethserver-onlyoffice-update