Probleme connect to a special SMTP Server

[tglomb]

Hello,
I must send Emails to a non-public SMTP Server.
First question: what is the max bytes possible for an attachement ?

My code works with public Email Server. It is similar to the NT example ;-)
The specific problem with this special SMTP Server is with the Username, it is a complex string. Here a part of the Log:

 >> AUTH LOGIN
 << 334 VXNlcm5hbWU6
 >> c..........................up to 100 characters...................................................................p
L.............................................up to 80 chars................................................4=
 << 501 5.5.4 (Invalid command arguments)

Inbetween the p and the L here is a CrLf. This is not in the Entry (or string variable) ! So it is added - maybe- by the SendMail() method of the NetWebClient class in the encryption (base64) process I guess. So error 501 is correct because this user is not existent at this Server.
How can I avoid the internal (?) similar to the StringTheory method Base64Encode parameter NoWrap ?
Any hints are appreciated.
TIA, Thomas
Clarion 10.12799, NT 8 and 11

ps the username has the following syntax. It is really to use as the Username in this case:
a_name@webname.abc.something#anothername.anything1.anything2.anything3:465#anything4#any5#any6#any7