Messages to and from "gmail" not working

There are many factors that might end up blocking emails on both endings, riseup and gmail.

First, send a test email with just a simple text and check if it arrives on the final account. Remember to check the Spam folder. If it does not land in any folder, then verify that the email address you are using matches the one you are using to probe the mail reception. The mail should land on Inbox or Spam or some folder on the account, if not it should be bounced back to the sender account with some error message. If that does not happen, then most probably is an wrong address issue.

BTW, just tested the riseup <-> gmail and it worked on both directions using my tests accounts.

Great it finally worked. Myabe it was a temporal network issue, sometimes when our infrastructure is being under DDoS attacks the mail delivery might be affected to (usually it is just delayed anyways, not blocked).

Take care.