How to change the maximum message size limit on the server?

I have written a Python script which is send an email with an attachement, but i get always the same error message :

raise SMTPSenderRefused(code, resp, from_addr)
smtplib.SMTPSenderRefused: (552, b'5.3.4 Message size exceeds fixed maximum mess
age size', 'notification@company.com')

How can I change the maximum message size limit on the server to avoid this error message and send my email with the attachement correctly?

I UPDATED MY QUESTION WITH MY CODE:

emailfrom = "myemailadress"
    emailto = "1.person"
    emailto = "2.person"
    fileToSend = "data.csv"
    username = "user"
    password = "password"

msg = MIMEMultipart()
msg["From"] = emailfrom
msg["To"] = emailto
msg["Subject"] = "subject"
msg.preamble = "subject"

ctype, encoding = mimetypes.guess_type(fileToSend)
if ctype is None or encoding is not None:
    ctype = "application/octet-stream"

maintype, subtype = ctype.split("/", 1)

if maintype == "text":
    fp = open("data.csv")
    # Note: we should handle calculating the charset
    attachment = MIMEText(fp.read(), _subtype=subtype)
    fp.close()
elif maintype == "image":
    fp = open("data.csv", "rb")
    attachment = MIMEImage(fp.read(), _subtype=subtype)
    fp.close()
elif maintype == "audio":
    fp = open("data.csv", "rb")
    attachment = MIMEAudio(fp.read(), _subtype=subtype)
    fp.close()
else:
    fp = open("data.csv", "rb")
    attachment = MIMEBase(maintype, subtype)
    attachment.set_payload(fp.read())
    fp.close()
    encoders.encode_base64(attachment)
attachment.add_header("Content-Disposition", "attachment", filename="data.csv")
msg.attach(attachment)

#server = smtplib.SMTP("smtp.gmail.com:587")
server = smtplib.SMTP('smtp.upcmail.hu', 25)
#server.starttls()
#server.login(username,password)
server.sendmail(emailfrom, emailto, msg.as_string())
server.quit()

time.sleep(5) 

I don't know how can I change the maximum message size limit on the server, I am using Debian.