ERROR: rlm_sql (sql): No connections available and at max connection limit

[csm3105]

I have deployed a Freeradius 3.0 server with MySQL + Daloradius.
When I view the logs I get the following error:

```
root@server:/etc/freeradius/3.0# tail -f /var/log/freeradius/radius.log
Thu Apr 15 11:02:49 2021 : Warning: Please use tls_min_version and tls_max_version instead of disable_tlsv1_2
Thu Apr 15 11:02:49 2021 : Info: Loaded virtual server <default>
Thu Apr 15 11:02:49 2021 : Warning: Ignoring "ldap" (see raddb/mods-available/README.rst)
Thu Apr 15 11:02:49 2021 : Info: Loaded virtual server default
Thu Apr 15 11:02:49 2021 : Info:  # Skipping contents of 'if' as it is always 'false' -- /etc/freeradius/3.0/sites-enabled/inner-tunnel:336
Thu Apr 15 11:02:49 2021 : Info: Loaded virtual server inner-tunnel
Thu Apr 15 11:02:49 2021 : Info: Ready to process requests
Thu Apr 15 11:03:01 2021 : Error: rlm_sql (sql): No connections available and at max connection limit
Thu Apr 15 11:07:54 2021 : Info: Signalled to terminate
Thu Apr 15 11:07:54 2021 : Info: Exiting normally

````

Why is this error occurring? thanks

Or please, if someone is so kind to contact me and ask the questions I have, because all this is new to me and I have been working for several days to configure the server but I do not know what can be wrong.