Moodle networking (MNet)

# List of providers to load
[provider_sect]
default = default_sect
# The fips section name should match the section name inside the
# included fipsmodule.cnf.
# fips = fips_sect
# If no providers are activated explicitly, the default one is activated implicitly.
# See man 7 OSSL_PROVIDER-default for more details.
#
# If you add a section explicitly activating any other provider(s), you most
# probably need to explicitly activate the default provider, otherwise it
# becomes unavailable in openssl.  As a consequence applications depending on
# OpenSSL may not work correctly which could lead to significant system
# problems including inability to remotely access the system.
[default_sect]
# activate = 1

And change it that way :

# List of providers to load
[provider_sect]
default = default_sect
legacy = legacy_sect
# The fips section name should match the section name inside the
# included fipsmodule.cnf.
# fips = fips_sect

# If no providers are activated explicitly, the default one is activated implicitly.
# See man 7 OSSL_PROVIDER-default for more details.
#
# If you add a section explicitly activating any other provider(s), you most
# probably need to explicitly activate the default provider, otherwise it
# becomes unavailable in openssl.  As a consequence applications depending on
# OpenSSL may not work correctly which could lead to significant system
# problems including inability to remotely access the system.
[default_sect]
activate = 1

[legacy_sect]
activate = 1

Then restart apache2 or php-fpm, and try again.

You can also test the script I posted in my previous message to test if your php installation can seal a message with RC4

HTH

Olivier