The server cannot connect to the remote database, Workbranch can. What could be the problem?

Question

MySQL

There are two servers. The site is on server_1, the database is on server_2. Workbranch connects to the DB on server_2 without issue. But from server_1 it is not possible to connect to the database on server_2, error:
Can't connect to MySQL server on 'x.x.x.x' (110)
Server_1 also connects to the local database without problems, if this is important.
Port 3306 is open, listening on server_2. The telnet xxxx 3306 command on server_1 also gives an error:

Unable to connect to remote host: Connection timed out

What could be the problem? Maybe there is a ban on connecting to external servers? How to check it? How to allow access? There is full access to the servers.

Answer 1

Maybe it was already

Answer 2

obviously there is no route from server_1 to server_2:3306. and the muscle has nothing to do with it

Answer 3

if telnet xxxx 3306 from the car on which the workbench works ok, then the problem is most likely between server 1 and 2 (it can be a firewall, for example, on server1 or if there is a proxy between them, then on them, or some kind of tricky routing or God knows what, everything depends on the infrastructure where server 2 and server 1 are located).
in such a case, first try to read the firewall rules and what they prohibit / allow / redirect if it is difficult, then you can turn off the firewalls (extinguish iptables for example, if it is there) and check if the telnet response has changed, if not Linux, then put out what is there on the firewalls .
if telnet xxxx 3306 from the car on which the workbench works is not ok, then most likely you are connecting through an ssh tunnel and then see above.