Upload speed is almost 0 when using ZCC(any version)

Hello Techies,

Upload speed is almost 0 when using ZCC(any version). Checked without Zscaler, speed for upload and download is too good.User is working from home. Upload speed is 0mbps when using ZCC.What could be the issue here?This is the single user who is facing this issue as of now.
Please help!

Hi Shreya, the fastest way to get this resolved would be to open a support case. This will allow the shortest path to resolution with a support engineer diagnosing and suggesting the resolution.


I will but currently trying to find a solution without TAC…if you could help would be great

Do you know if you’re using DTLS or TLS? Some ISPs filter DTLS which can affect performance.

User is working from home and using ZAPP latest version and yes its TLS

Hi Shreya,

we also had issues with users running into “acoustic coupler” speed-ranges although they had quite fast connections without ZCC. You are talking about TLS so I assume you use zTunnel 2.0. Best approach from my experience:

  1. Create a dedicated app&fwd profile and assign that to the particular user
  2. Try Tunnel 1.0 and see if problems vanish (likely…)
  3. Try Tunnel 2.0, check/uncheck DTLS/TLS and reduce MTU

Nearly all issues we had with homeoffice users were related to their providers and connection types (as Keith already pointed out)


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Hi Manuel,

I had replied to your another post.
Can you provide me settings to do for DTLS/TLS and MTU?

Please see https://community.zscaler.com/t/ztunnel-2-0-dtls-tls-mtu/

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As soon as I asked you here,I found it- I missed to click on dropdown :wink:
ty btw!