Hello
This looks like a potential spoofed email. You need to first get yourself unblocked. Are you saying you cannot find your email address listed on the block list? If that's the case, any chance you did this on a phone? If so, check your phone's contact app, or contact settings, make sure you are not blocked there.
Next, can you use this instruction to get the email header that was sent by "yourself" https://support.microsoft.com/en-us/office/view-internet-message-headers-in-outlook-cd039382-dc6e-4264-ac74-c048563d212c
I would like to review this email header to determined if it is really spoofed, or indeed from you by someone hacking into your account.
When you share, please modify your email address to dummy ones to protect your privacy.