RV 345 no access to web interface

[Charles05]

Hello.
I have a RV345 router that does not allow me to access its web interface.
I did a factory reset, but the problem remains the same, it remains on the login screen after having entered the username and password ("cisco" in both cases).
According to what I've read on forums, it may be a problem with the firmware version.
My question is, how do I change the firmware if I can't access the web interface?
Any suggestions?
Thank you in advance for your help

[marce1000]

 - Try with Google Chrome  : press F12 first, then try to login, what output(s) do you get in the development pane  ?

 M.

[Charles05]

Thanks, for your help.
The development panel shows:
->POST https://192.168.1.1/jsonrpc 502 (Bad Gateway)
get login data error                                    login.html:222

[marce1000]

- That's an internal error on the
device. Try power cycle or factory reset (included)

M.

[Charles05]

Yes, I have done it, but the same error remains. I don't have access to the web interface.
I read in one of the posts that it is due to a problem in a firmware update, the solution can be seen by going back to the previous firmware.
But how to do it without accessing the web interface. Do you know how?

Thanks for your time.
Carlos

[SamirD]

See this thread as I think the same things should work for your model:

https://community.cisco.com/t5/routers-small-business/rv340-unable-to-login-to-admin-portal/td-p/4185895/page/4