3315977 - Admin Task Scheduler (ATS) is blocked by SQL1226N The maximum number of client connections are already started

The db2diag.log reports messages like 

2023-01-16-11.26.01.832458+060 E257546E531           LEVEL: Warning
PID     : 00000                TID : 140270343546624 PROC : db2acd 
INSTANCE: db2<SID>               NODE : 000
HOSTNAME: XXXXXXXXXX
EDUID   : 16                   EDUNAME: XXXXXXX
FUNCTION: DB2 UDB, Administrative Task Scheduler, AtsTask::run, probe:200
MESSAGE : ZRC=0xFFFFFB36=-1226
SQL1226N  The maximum number of client connections are already started. 

2023-01-16-11.26.01                                  LEVEL: Info
PID     : 00000                TID : 140270343546624 PROC : db2sysc 0
INSTANCE: db2<SID>               NODE : 000
HOSTNAME: XXXXXXXXXX
EDUID   : 16                   EDUNAME: XXXXXXX
FUNCTION: DB2 UDB, base sys utilities, sqeAgentServices::RequestAgentForAppl, probe:2081
MESSAGE : ZRC=0xFFFFFB36=-1226
SQL1226N  The maximum number of client connections are already started.
DATA #1 : <preformatted>
The number of background tasks has reached the limit of 20, will try again later.

2023-01-16-11.26.01.832458+060 E257546E531           LEVEL: Warning
PID     : 00000                TID : 140270343546624 PROC : db2acd 
INSTANCE: db2<SID>               NODE : 000
HOSTNAME: XXXXXXXXXX
EDUID   : 16                   EDUNAME: XXXXXXX
FUNCTION: DB2 UDB, Administrative Task Scheduler, AtsTask::run, probe:201
MESSAGE : ADM15502W  The administrative task scheduler could not execute task 
          "SAPTOOLS.DBH <Collector Name>" because the database is inactive.
DATA #1 : ZRC, PD_TYPE_ZRC, 4 bytes

Db2 LUW IBM

ADM15502W  The administrative task scheduler could not execute task , KBA , BC-DB-DB6-DBA , Database Administration , Problem