I don't know ISPConfig but I guess your upgraded Roundcube install is still in /usr/share/roundcubemail. Is it an upgrade you got through ISPConfig or did you do it manually?

A major change with Roundcube 1.7 is that the public_html dir became the web root. So may be this works?

Alias /roundcubemail /usr/share/roundcubemailpublic_html
Alias /webmail /usr/share/roundcubemail/public_html

<Directory /usr/share/roundcubemail/public_html/>
...

Assuming the above does not solve your issue, can you describe what the specific problem is you are facing?

I've had an ISPConfig / Roundcube v1.x /Apache (CentOS/Rocky) server for years - I really like the fact that one installation of RC could be used on all domains by default by just including one httpd/rc.conf file that contained
Alias /roundcubemail /usr/share/roundcubemail
Alias /webmail /usr/share/roundcubemail

# Define who can access the Webmail
# You can enlarge permissions once configured

<Directory /usr/share/roundcubemail/>
        Options none
        AllowOverride Limit
        Require all granted
</Directory>zero other configuration needed for any domain (100's) added to the server, it was instantly available as a mail client to all domains.  also, it was not the default webpage for a domain, and clients only knew it was available if I informed them.
I haven't found a configuration for v1.7 that does the same thing - it appears I need to define a unique site in Apache for roundcube, with a defined DocumentRoot.
<VirtualHost *:80>
     DocumentRoot /var/www/roundcubeemail
     ServerName anydomain.netOr something like that - it's not clear to me how roundcube could be set up like before and have it be fully integrated and seemless (never leaving the customers domain).
Did I miss a discussion that covered this, or an example that does this?
Thanks.

There is definitely something odd about this hotel.
I opened the server firewall for this IP then tried using K9Email.
I could receive but not send.
Then I fired up a VPN connection to my server and K9 could send (but not roundcube).
I'm home next week so will live with that for now.
Thanks for your help.

Thanks again for the great program.

Hi SKaereo, thanks for your reply. Yes, the tables were corrupted. I couldn't find a way to repair them—it didn't lead anywhere for me. I created a new database using the installer script instead. I did lose a bit of data, but nothing major.

It should since Roundcube is sending the email from the server its hosted on so the IP shouldn't be changing.

It seems that my mailserver cannot reverse DNS lookup my hotel and that the hotel does not have a valid SPF record.
Could either of these affect roundcube?

Source of my issue is this commit: https://github.com/roundcube/roundcubemail/commit/374a4a5e25048f99cbded5be3fb7edec0605885f
It changes Mail_mime 'html_encoding' parameter from a fixed 'quoted-printable', to 8bit for most cases. Mail_mime does not wrap lines for 8bit, only when html_encoding is quoted-printable or base64.

I will add my finding to the original issue on Github as well.

It sounds like the database is corrupted, see if this fixes the issue: https://dba.stackexchange.com/questions/56849/innodb-tablespace-is-missing-for-table

That would point to the mail server doing something odd, maybe enable smtp_debug and post that log?