Recommend to check the Accept cookies from sites and set Accept third-party cookies to Never. As blocking all cookies which include first-party cookies would cause an error. Can’t confirm if other services like Yahoo! and other email providers would cause the same error for Mozilla Thunderbird. I don’t think there’s a point to blocking first-party cookies.
this is definitely caused by something else. Blocking third party cookies does not break any notable websites.
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This was caused by blocking first-party cookies as seen in the picture. I’ve tried it myself. Otherwise it would’ve worked if I had not made this setting change.
You two are talking about the same thing 
- One said set
Accept cookiesand block3rd-party cookies, - One said
Blocking 3rd-party cookies does not break any notable websites
then i do not understand your remarks. We do not recommend blocking first party cookies.
Let me clarify. The current PG Email Client guide for Thunderbird has the recommendation Uncheck Accept cookies from sites meaning even first-party cookies are blocked if this setting is unchecked.
hmm okay well i guess thst was not intended/tested for people who regardless of other recommendations still use google mail. I still think this setting would be recommended for all cases we do recommend. Using google mail already does not follow that so i guess then things mighy not work.
I have a gmail account on Thunderbird with cookies disabled and I don’t experience any breakage. At what point do you have that error?
It’s probably due to setting up a new account, try to enable cookies and when the account is added disable them again.
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It seems this issue only does occur during setup.
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@ph00lt0 maybe we could add a disclaimer on the site for that.
sure, if you want just open a PR and link this discussion.
@ph00lt0 @user1 I took the liberty of opening one 
Please let me know if the wording should be changed.
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Yeah, this is what I had to do when setting up my gmail.
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Has anyone experienced the “Uncheck Accept cookies from sites” recommendation breaking email logins other than Gmail’s? I made changes to the above PR to specify that this is a Gmail issue, since @ph00lt0 raises a good point here:
Yes, the Microsoft365 login (https://login.microsoftonline.com) doesn’t work without them.
I also want to add that in my case, when logging to Microsoft365, at one point I need to go through the logging process on my employer’s website. It gets redirected to it automatically from Microsoft365, and then it goes back to Microsoft365 again after entering the credentials. I assume that the process will be similar in other similar institutions. Basically, what I’m trying to say is that it’s not only Google or Microsoft that may need those cookies enabled, but also the intermediary login sites of those institutions.
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Thanks for sharing your experience!
I’ve modified the note to include the use case you shared:
You may need to keep this setting checked when you’re logging in to some providers such as Gmail, or via an institution’s SSO. You should uncheck it once you log in successfully.
What happens when the cookies expire? Does the login still work then or do need to re-enable accepting cookies in order to log in again? Google’s cookies have a long expiration date of 2 years, but some of the Microsoft’s ones have an expiration date of just 1 week or 1 month.
I also remember that I had to enable cookies (and keep them enabled) when using https://addons.thunderbird.net/thunderbird/addon/owl-for-exchange to connect with a Microsoft Exchange account, or otherwise it would prompt to log in every time when starting Thunderbird.
In my experience cookies are needed one time only just to setup the account to grant Thunderbird the use of the mailbox. I think they’re needed for the webpage of the email provider website to work properly not for Thunderbird itself.
I have used gmail and microsoft accounts with cookies disabled without any problem after that initial setup.