How to specify an html file as DirectoryIndex?

Question

htaccess

Exported the site in tilde to a separate server.
By default, all tilde pages are exported as html files.
Transferred to the server, all html files open, but how can I make the directory of the file I need open initially?
In the htaccess settings it's worth
DirectoryIndex page11555437.html
But still, when entering the domain, it shows a 403 error. If you create a php file, it opens it immediately. It feels like he doesn't see the DirectoryIndex. What could be the problem?

Whole htaccess file:

ErrorDocument 403 /page20136428.html
ErrorDocument 404 /page20136428.html

DirectoryIndex page11555437.html

RewriteEngine On

RewriteCond %{REQUEST_FILENAME} /robots.txt
RewriteCond "%{DOCUMENT_ROOT}/robots_%{HTTP_HOST}.txt" -f
RewriteRule ^(.*)$ robots_%{HTTP_HOST}.txt [NC,L]
RewriteRule ^new$ page22523437.html [NC]
RewriteRule ^new/$ page22523437.html [NC]

RewriteRule ^about$ page22523520.html [NC]
RewriteRule ^about/$ page22523520.html [NC]

RewriteRule ^services/zagotovka$ page22523607.html [NC]
RewriteRule ^services/zagotovka/$ page22523607.html [NC]

RewriteRule ^services/postavka$ page22566691.html [NC]
RewriteRule ^services/postavka/$ page22566691.html [NC]

RewriteRule ^services/svarka$ page22566955.html [NC]
RewriteRule ^services/svarka/$ page22566955.html [NC]

RewriteRule ^services/obrabotka$ page22567040.html [NC]
RewriteRule ^services/obrabotka/$ page22567040.html [NC]

RewriteRule ^services/metiz$ page22567059.html [NC]
RewriteRule ^services/metiz/$ page22567059.html [NC]

RewriteRule ^services/add$ page22567079.html [NC]
RewriteRule ^services/add/$ page22567079.html [NC]

RewriteRule ^partner$ page22568339.html [NC]
RewriteRule ^partner/$ page22568339.html [NC]

RewriteRule ^services$ page22594928.html [NC]
RewriteRule ^services/$ page22594928.html [NC]

RewriteRule ^blog$ page22762026.html [NC]
RewriteRule ^blog/$ page22762026.html [NC]

RewriteRule ^contacts$ page22763412.html [NC]
RewriteRule ^contacts/$ page22763412.html [NC]