This has been an ongoing problem for some time and have seen many posts about this concern with no real fix
Issue:
Maximum number of concurrent DNS queries reached (max: 150)
Running pihole on a Rpie
Pi-hole v5.12.2
FTL v5.18.1
Web Interface v5.15.1
The only way I can clear the issue is rebooting the device, but it seems to come back. Is there any actual fix to address this concern, is it something to do with the cache?
My skills in SSH are not the best, so if there is a guided solution to address this concern I am all ears.
Per our documentation (which is linked under each diagnostic warning):
The configured maximum number of concurrent DNS queries for a given server is reached. The system is either very busy at the moment or not receiving queries from the configured upstream. Check your connectivity or the upstream DNS server status.
The warning can also be printed when being spammed with an excessive amount of duplicates or when the upstream server never replies for specific domains. Check your logs and try to identify similarities between the query directly preceding this warning and earlier queries in /var/log/pihole/pihole.log. Try to find out if your upstream does maybe never reply to specific domains and fix this.
This warning is printed at most once every five seconds (per upstream server) to help mitigate unlimited log file growth.