New member doesn't get "opt-in" letter from our site (spam folder checked)

Dear IT helpers,

We have a new member - Sheryl D. Hunter (Sheryldhunter@gmail.com). We, as usually we do, place her name, email, telephone number in our system, but she doesn't get letters from our site. Tried so many times.

1960northhouston.toastmastersclubs.org/directions.html
Club N: 2659 (District 56)

I see no other emails to her in last 4 weeks.

I have resent the opt-in email using the pull down in the member tools.
I can see gmail accepting the email.

Apr 14 23:55:59 toastmastersclubs sendmail[27069]: 13ENtwST027066: to=<sheryldhunter@gmail.com>, ctladdr=<server@toastmastersclubs.org> (501/502), delay=00:00:01, xdelay=00:00:01, mailer=esmtp, pri=122261, relay=gmail-smtp-in.l.google.com. [172.217.197.26], dsn=2.0.0, stat=Sent (OK 1618444559 u15si687934qkp.204 - gsmtp)

Thank you sooooooooo much, Brian! Sheryl has gotten our letter and is already on our site.