# Pkg.add proxy authentication required, but no callback provided

**URL:** <https://discourse.julialang.org/t/pkg-add-proxy-authentication-required-but-no-callback-provided/10244>\
**Category:** General Usage\
**Created:** [April 9, 2018, 12:00pm UTC](https://discourse.julialang.org/t/pkg-add-proxy-authentication-required-but-no-callback-provided/10244 "2018-04-09T12:00:45Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![johnh](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/johnh/32/3615_2.png) [@johnh](https://discourse.julialang.org/u/johnh)\
**Post date:** [April 9, 2018, 12:00pm UTC](https://discourse.julialang.org/t/pkg-add-proxy-authentication-required-but-no-callback-provided/10244/1 "2018-04-09T12:00:45Z")

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Help! I am stuck in a maze of twisty packages.  
I am behind a corporate firewall, though I can set the variable http\_proxy and run a git clone from the bash command prompt. In the Julia REPL I get this failure:

ulia\> Pkg.add(“Elly”)  
INFO: Cloning cache of ArgParse from [https://github.com/carlobaldassi/ArgParse.jl.git](https://github.com/carlobaldassi/ArgParse.jl.git)  
ERROR: Cannot clone ArgParse from [https://github.com/carlobaldassi/ArgParse.jl.git](https://github.com/carlobaldassi/ArgParse.jl.git). proxy authentication required, but no callback provided

I know this is a common failure, and is related to libgit2. Any hints and tips please?  
Julia Version 0.6.2  
Commit d386e40c17 (2017-12-13 18:08 UTC)  
Platform Info:  
OS: Linux (x86\_64-pc-linux-gnu)  
CPU: Intel(R) Xeon(R) CPU E5-1660 v2 @ 3.70GHz  
WORD\_SIZE: 64  
BLAS: libopenblas (USE64BITINT DYNAMIC\_ARCH NO\_AFFINITY Sandybridge)  
LAPACK: libopenblas64\_  
LIBM: libopenlibm  
LLVM: libLLVM-3.9.1 (ORCJIT, ivybridge)

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**Author:** ![johnh](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/johnh/32/3615_2.png) [@johnh](https://discourse.julialang.org/u/johnh)\
**Post date:** [April 9, 2018, 12:11pm UTC](https://discourse.julialang.org/t/pkg-add-proxy-authentication-required-but-no-callback-provided/10244/2 "2018-04-09T12:11:48Z")

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[https://github.com/JuliaLang/julia/issues/25245](https://github.com/JuliaLang/julia/issues/25245)  
☹ If Viral B Shah is puzzled…

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<div class="post-metadata">

**Author:** ![johnh](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/johnh/32/3615_2.png) [@johnh](https://discourse.julialang.org/u/johnh)\
**Post date:** [April 10, 2018, 4:37pm UTC](https://discourse.julialang.org/t/pkg-add-proxy-authentication-required-but-no-callback-provided/10244/3 "2018-04-10T16:37:50Z")

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I am adding this observation, in case anyone else has the same problem in the future.  
Our particular proxy sems to succees sometimes, then fail. I am not aware of the exact architecture, I imagin ethough this indicates a load balancer where one fails ???  
For instance:  
INFO: Cloning cache of IJulia from [https://github.com/JuliaLang/IJulia.jl.git](https://github.com/JuliaLang/IJulia.jl.git)  
INFO: Cloning cache of JSON from [https://github.com/JuliaIO/JSON.jl.git](https://github.com/JuliaIO/JSON.jl.git)  
INFO: Cloning cache of Nullables from [https://github.com/JuliaArchive/Nullables.jl.git](https://github.com/JuliaArchive/Nullables.jl.git)  
ERROR: Cannot clone Nullables from [https://github.com/JuliaArchive/Nullables.jl.git](https://github.com/JuliaArchive/Nullables.jl.git). proxy authentication required, but no callback provided

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**Author:** ![amellnik](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/amellnik/32/137_2.png) [@amellnik](https://discourse.julialang.org/u/amellnik)\
**Post date:** [April 10, 2018, 11:43pm UTC](https://discourse.julialang.org/t/pkg-add-proxy-authentication-required-but-no-callback-provided/10244/4 "2018-04-10T23:43:50Z")

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If this works sometimes for some packages but not others I would assume it’s an issue with your proxy rather than anything on the Julia side.