So, i use this bulk messaging service and they decided to make logins OTP only ("for security reasons", they say), sent to your email.
So instead of entering a password quickly,
- enter the password for your email account,
- click about 10 times on Resend OTP
- wait for OTP
- copy OTP and paste in the box.

So basically relying on the person's email provider's security than deploying their own.