SMTP error "Cannot send message - "5.7.0 From address is not one of your addresses"

[SMTP]Cannot send message (‘From’ field address ‘lewlin68@gmail.com’ not accepted due to the following reason:
"5.7.0 From address is not one of your addresses
")

martes 12 octubre 2021 :: 1725hrs (UTC +01:00)

Hi @w5lew

More information needed.
Has it ever worked?
Are you using Windows or Mac? - What version?
How is your SMTP setup?
Can you receive email?
What version of eMC?

¡Saludos desde la soleada Sevilla en España!
¡Mis mejores deseos y mantente a salvo!

Skybat
emc_forum@compucall.com

Hablo español, luego portugués e inglés, con conocimiento de varios otros idiomas.

Skybat, thanks for your help.
Yes, it has worked before. Using Windows 10, latest version, I assume.
Can receive email. Outbox has 72 msgs waiting!!!
eMC version 8.2.1515 (b178bb5

martes 12 octubre 2021 :: 1813hrs (UTC +01:00)

Hi @w5lew

Please update to latest version at:

Run eMC after update to confirm is either working or not.
Do you have a Pro or Free version of eMC?
Please confirm IMAP or POP3 and advise your settings.
When did this issue first occur?
What had you done immediately prior to the issue?
How many email accounts do you have?
Have you been making Backups of eMC using the inbuilt facility?

¡Saludos desde la soleada Sevilla en España!
¡Mis mejores deseos y mantente a salvo!

Skybat
emc_forum@compucall.com

Hablo español, luego portugués e inglés, con conocimiento de varios otros idiomas.

Updated to the latest version - thank you.
I have the Pro Version
gmail acct
IMAP xxxx /993/ Use SSL/TLS on special port (legacy)
SMTP / 587 / Force usage of SSL/TLS
iCloud.com acct:
IMAP limap.mail.me.com / 993 / Use SSL/TLS on special port (legacy)
SMTP: / 587 / Force usage of SSL/TLS - Server requires authentication checked / Use these credentials - checked with user name w5lew and password
This issue has occurred before, a couple of months ago. I found a fix on the eMC support website (I think) and it worked. Guess it was a temporary fix because it happened again.
I didn’t know that my iCloud outbox had not been sending for several days/weeks so I don’t know what I would have done prior - sorry.
I have 3 email accounts.
Don’t think I have been making backups of eMC. Guess I need to find some instructions and start doing that!
Muchisimas gracias,
Lew