EmailSender and SMTP DATA error! SMTP Response TIMEOUT!

Hello, I use the Email Sender library with Mega Arduinos with mail provider laposte.net and gmail.com (via SendGrid), both on SMTP 587. I try each time to send an email 4 times (tests stop if resp.code=0) once with laposte.net, once with SendGrid, once with laposte.net and the last with SenGrid. I sometimes have during attempts to send emails a resp.code = 1 with the message SMTP DATA error! SMTP Response TIMEOUT 4 times in a row! So if the problem that generated the request to send an email is still present at the next check, I start 4 tries again and so on, if an email goes well, I don't send any more for 24 hours. My problem is that despite the error message: SMTP DATA error! SMTP Response TIMEOUT! I receive an email (not 4 emails but 1email), despite resp.code =1.... It's an email from SendGrid (gmail.com) that ended up working and it drowns me in emails (one every 6 minutes or so). What is SMTP DATA error! SMTP Response TIMEOUT! and how to fix it? My internet connection works well (I test it via a connection to Google) Here is what my error log looks like: 6/5/2023 14:16:33 1, SMTP DATA error! SMTP Response TIMEOUT! 6/5/2023 14:17:3 -1, 395, = connected Google 6/5/2023 14:17:34 1, SMTP DATA error! SMTP Response TIMEOUT! 6/5/2023 14:18:4 -1, 395, = connected Google 6/5/2023 14:18:5 1, SMTP DATA error! SMTP Response TIMEOUT! 6/5/2023 14:18:36 -1, 395, = connected Google 6/5/2023 14:19:6 1, SMTP DATA error! SMTP Response TIMEOUT! And I received an email at 2:17 p.m. via SendGrid (Gmail.com) THANKS