Fixing the broken iOS simulator in React Native when using zscaler

David Fekke
3 min readApr 10

If you are using zscaler and are trying to run the iOS simulator with the React Native metro server, you may have run into the issue of not being able to pull in content from your metro server while zscaler is running. Turning off Internet Security might allow this to work, but the real reason the simulator cannot access the metro server is because the simulator does not have the zscaler certificate installed. Here is how you can fix this in your simulator.

Zscaler certificate

Zscaler has a security certificate that it installs on your computer to let you access resources on your zscaler network. You can download this certificate from zscaler on mobile devices by using the following URL:

You can download this using your terminal using the following command:

$ curl --output ~/zscalerrootca.der

Selecting the correct iOS simulator

Xcode installs many simulators, but generally you only run one at a time. The following command will show all of your simulators that are installed.

$ xcrun simctl list devices

You should see a list that looks something like this:

== Devices == 
-- iOS 16.2 --
iPhone SE (3rd generation) (1B53E6A9-522B-42FD-96CA-FECD651698F5) (Shutdown)
iPhone 14 (04D2D6E0-A89E-4401-8809-FCE0982A4397) (Shutdown)
iPhone 14 Plus (7860E3BC-8D14-47B1-B64F-41B405BF3054) (Shutdown)
iPhone 14 Pro (6A686E6D-2A0A-4D2B-9B77-8517D97CCD4F) (Shutdown)
iPhone 14 Pro Max (205ACFE7-18C2-4283-BE93-AB21CA1894F5) (Shutdown)
iPad Air (5th generation) (EE9C9096-D588-4DF7-82AA-938119080A14) (Shutdown)
iPad (10th generation) (08F02635-A08F-403C-828E-19527CB4BCBD) (Shutdown)
iPad mini (6th generation) (2CF3CE52-A1F5-42BE-8BA3-1E65B68553F0) (Shutdown)
iPad Pro ( 11-inch) (4th generation) (E0B10CB8-057E-49BF-9268-B1D3EA106CB7) (Shutdown)
iPad Pro ( 12.9-inch) (6th generation) (00673013-72C8-4BE2-ACD9-83AD75841A1D) (Shutdown)
-- Unavailable: --
iPhone 14 Pro (92DB7E6A-E7FB-4FE2-9859-B040A163B393) (Booted)
iPhone SE (3rd…
David Fekke

I am a software engineer and commercial pilot in jacksonville, Fl. I also produce videos for the Polyglot Engineer Channel on YouTube.