Timeouts again and again when trying to establish connections to DBs when using toad db2

I (and many other colleagues) have the problem that when I try to connect to one of the databases a timeout occurs. This happens with different clients (TOAD via Citrix, TOAD Db2 locally) .It is possible that two attempts fail, the third then works. The error message is attached.

i have checked from various level but unable to find RCA why its not connecting all the time.
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need urgent support on this from admin end.

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