`.server` is just part of the file-name. There is no such thing as a file-extensions (there was on MS-Windows pre Windows-95, and in CPM ).
The problem is the file-type: it is an executable `ELF 64-bit LSB shared object, x86-64, version 1 (GNU/Linux), …`. The important part of this is `x86-64`, it is the CPU architecture. The Pi has an `ARM` CPU: it is not an `x86`.
Options:
* Get a version of the program that is compiled for your OS and hardware.
* Obtain source code and ask/pay someone to compiled for your OS and hardware.
* Obtain source code and Compile the program for your OS and hardware.