Connection problems since day 1

I've been a paying customer for a week or so. Every evening I log in to the webmail, and I'm met with some kind of connection error.

On bad days, I get some sort of JSON displayed in my browser saying my credentials are invalid. Then I try logging in again, and if I'm unlucky, I get the same response. Eventually it goes through, though.

Then, on other days, after having logged in, I'm greeted with an error mentioning some other problem with my credentials, which apparently may happen if I recently changed my password (which I haven't), and that I have to log in again. Then I log out/in again, and maybe the error disappears. Lately, I've come to ignore the error, since the UI seems mostly functional. Admittedly, sometimes some mail folders are missing in the list. Navigating to settings and back again seems to sometimes bring them back.

Sometimes I also get some error when having submitted the password to Guard, while trying to open an encrypted mail. Then I reenter my Guard password, and it goes through just fine.

Finally, like many others, I was also affected by the seemingly well-known error of not being able to send mails with a new account, requiring a support ticket. And since I submitted thursday or so, of course there was no response over the weekend.

My connection is fine. I'm sitting on a rock-solid 1gbit fiber, pinging ~8ms to servers in my own country, which is bordering up to Germany where mailbox is hosted.

All in all I have to say that my experience so far has been disappointing. The webmail feels so unstable and at the end of the day unreliable. I waited a week or so with reaching out with these connection problems, giving mailbox the benefit of the doubt. But as the days went by, this pattern continued, and my dissatisfaction grew.

I cannot begin to conclude what the root cause is, but it seems to me the experience is akin to using a service that's overloaded.

Am I the only one experiencing lots of seemingly connection-related problems?