Email not sending

I have been trying for the past two weeks to reset my password for my nextcloud storage server and it is refusing to send me the email. I have made sure multiple times that the right email is typed in and I know that it is the correct email because when I log into my nextcloud server on my phone I can view the email address, but I cannot change password.(it automatically logs into the phone) I don’t have anything special set up on my internet that would cause it to be blocked. Does anyone have a solution?