I am thinking that maybe you should've uninstall Acrobat Pro 2017 first, before installing the older unsupported version of Acrobat Pro XI.
And to be on the safe side, I would've run the Acrobat Cleaner and Repair tool to remove old traces of the software in whatever machine this installation package (.msi) was executed from.
After a successful installation of Acrobat Pro XI you must also manually install the latest version update for that product to avoid further problems.
However, since you've mentioned about Citrix VDA taking too long to load Acrobat Pro XI, I think that you need to re-verify what method are you currently using for the VDA registration.
Please review the Citrix VDA guidance below, to see if you've missed a step, or using the incorrect registration method, or if some of the DNS's are not matching the VDAs controller(s) addresses as listed in the ListOfDDCs: