gmail broken on ReadyNAS 6.10.4

[mpsharp]

Seeing the exact same issue described here, but there was no fix or work-around:  https://community.netgear.com/t5/ReadyNAS-Beta/ReadyNAS-6-10-3-Broke-Gmail-again/m-p/1895808

Can anyone help?

[mpsharp]

More info: When the popup hangs (Firefox 88.0) I get the following errors in the console:

Opening multiple popups was blocked due to lack of user activation. frontview_6.10.10660.610040016.js:5382:50

Uncaught TypeError: input is null

    decode http://192.168.1.12/oauth2EnDeCryption.js:47

    OAuth2EnDeCryption http://192.168.1.12/oauth2EnDeCryption.js:349

    initialize http://192.168.1.12/emailservicecb.html:18

    onload http://192.168.1.12/emailservicecb.html:1

oauth2EnDeCryption.js:47:9

[mpsharp]

And just tried it on Chrome for kicks:

oauth2EnDeCryption.js:47 Uncaught TypeError: Cannot read property 'replace' of null
    at Object.decode (oauth2EnDeCryption.js:47)
    at OAuth2EnDeCryption (oauth2EnDeCryption.js:349)
    at initialize (emailservicecb.html:18)
    at onload (emailservicecb.html:28)

[StephenB]

FWIW, I am getting gmail alerts with 6.10.4 (and also got them with 6.10.3).  

But I am not using an app-specific password.