Unable to open https://www.jotform.com/ (Err 403) since v6.5.0

[Enkidu70]

What happened?

I use latest Waterfox 6.5.1 on Linux Mint 21.3.

Since autoupdate installed v6.5.0, I am not able to open https://www.jotform.com/ - the only thing displayed is "403" as single number in upper left corner.

Before 6.5.0 I was able to use https://www.jotform.com/ as usual.
Page opens fine in latest firefox.

When I set e.g. user agent "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:126.0) Gecko/20100101 Firefox/126.1" jotform opens as usual.
When I seit it back to Waterfox original "Mozilla/5.0 (X11; Linux x86_64; rv:128.0) Gecko/20100101 Firefox/128.0" I am not able to access jotform.
(Firefox uses "Mozilla/5.0 (X11; Linux x86_64; rv:132.0) Gecko/20100101 Firefox/132.0")

Why that?

Reproducible?

• I have checked that this issue cannot be reproduced on Mozilla Firefox.

Version

G6

What platform are you seeing the problem on?

Linux

Relevant log output

[wbak1102]

Opens without a problem.

[woahbust]

I'm getting most likely the same issue with Waterfox 6.5.1 on Windows 10. Trying to load certain websites will result in an SSL_ERROR_BAD_CERT_DOMAIN error and after clicking "Accept the Risk and Continue", the site only shows 403 Forbidden cloudflare. I also tested on 6.5.0 and the same thing happened. I haven't tested on other versions but I don't remember having this issue before. Two sites that cause this issue for me are chatreplay.stream and tf2classic.com

[hiiiha]

I do not have this problem either. Try to use a proxy

[ibrahimBeladi]

Change the UserAgent and it shall work for you

[woahbust]

Change the UserAgent and it shall work for you

I tried different user agents and the issue persists.

[woahbust]

I have found a solution that seems to work:
go to about:config,
set security.tls.version.fallback-limit to 4 (default) and set security.tls.version.max to 4 (default)
or alternatively open prefs.js in your waterfox user root folder and delete the corresponding user_pref() lines.