# Certificate installation problems on Ubuntu/Firefox
**URL:** https://discourse.mitmproxy.org/t/certificate-installation-problems-on-ubuntu-firefox/625
**Category:** help
**Created:** [September 3, 2017, 3:49pm UTC](https://discourse.mitmproxy.org/t/certificate-installation-problems-on-ubuntu-firefox/625 "2017-09-03T15:49:20Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@phani-vadrevu](https://discourse.mitmproxy.org/u/phani-vadrevu)
#### Post date: [September 3, 2017, 3:49pm UTC](https://discourse.mitmproxy.org/t/certificate-installation-problems-on-ubuntu-firefox/625/1 "2017-09-03T15:49:20Z")
I am using Firefox 53 on Ubuntu 14.04. In order to install the mitmproxy certificate, I visited [http://mitm.it](http://mitm.it), clicked on “Other” and downloaded the certificate.
However, this doesn’t seem to be sufficient. I still get the an error whenever I try to visit a HTTPS website on my browser.(See attached image). Am I missing something here? Please help me out.
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### Author:  [@phani-vadrevu](https://discourse.mitmproxy.org/u/phani-vadrevu)
#### Post date: [September 3, 2017, 4:18pm UTC](https://discourse.mitmproxy.org/t/certificate-installation-problems-on-ubuntu-firefox/625/2 "2017-09-03T16:18:43Z")
I also tried to import “mitmproxy-ca-cert.pem” by going to the “Certificate Manager” (Authorities) dialog in Firefox. After importing, I don’t see any certificate under the name “mitmproxy”. I am not sure why this isn’t working.
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### Author:  [@phani-vadrevu](https://discourse.mitmproxy.org/u/phani-vadrevu)
#### Post date: [September 3, 2017, 7:23pm UTC](https://discourse.mitmproxy.org/t/certificate-installation-problems-on-ubuntu-firefox/625/3 "2017-09-03T19:23:15Z")
I was able to get around this by removing Firefox, deleting the profile directory and re-installing Firefox.
`sudo apt-get remove firefox`
`rm -rf ~/.mozilla`
`sudo apt-get install firefox`
After this, just visiting [mitm.it](http://mitm.it) and downloading the certificate was enough to get mitmproxy to work.