How to sudo through a startup message

Hello,

I'm connecting with my limited user to a server and do a sudo su - rootuser after that.

This works fine, until the logon has a startup message. Then I get this error on the sudo command:

Error skipping startup message. Your shell is probably incompatible with the application (BASH is recommended)

See: https://winscp.net/eng/docs/message_startup_message

I'm using it with SCP and the shell command sudo su - rootuser.
Without the sudo su command, there is no problem with the startup message

So, how can I sudo with a startup message?

When I connect with Putty (SSH), I'm getting the startup message, when I login with my limited user. When I'm doing the sudo su, I'm not getting another startup message.

Since I'm not having root rights on the server, I'm not able to configure the user or the startup message different!

I'm using WinSCP 5.5.0 (Build 3839).

Thank you for your help,
bobbel

As I've asked you already on stackoverflow, please attach a full log file showing the problem (using the latest version of WinSCP).

Here is the full log file.
I replaced the host with myhost, the limited user with myuser and the sudo user with rootuser.

Also, as you can see, I've already updated to the latest version:

WinSCP Version 5.5.2 (Build 4130) (OS 6.1.7601 Service Pack 1 - Windows 7 Enterprise)

Unfortunately it doesn't work either.

The key is:

sudo: no tty present and no askpass program specified

See comment on requiretty at:
https://winscp.net/eng/docs/faq_su

Thanks for your answer!

So, finally, I'm not able to do the task, since I'm not allowed to edit the /etc/sudoers file to turn off the requiretty option (if it's turned on... I'm not sure since I cannot access this file...).

However, you helped me a lot to find out, how to theoretically solve the problem - thank you! ;)