Hello. I do not know if this place is the right section to solve client problems or not. Let me know if it's wrong and if you can, please move the topic to its right place.

Issue: Player cannot run the client.jar without VPN.
Problem output via command prompt "java -jar client.jar":
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C:\Users\example>java -jar client.jar
Picked up _JAVA_OPTIONS: -Djava.net.preferIPv4Stack=true
Error with the sprite updater!
Error in version check!
Could not retrieve remote version file. Server is either offline or the remote file is corrupt.

Please try again in a few minutes.
java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(Unk nown Source)
at java.util.ArrayList$Itr.next(Unknown Source)
at rs.f.c.c.b(Unknown Source)
at rs.f.c.c.a(Unknown Source)
at rs.Client.e(Unknown Source)
at rs.Client.u(Unknown Source)
at rs.ar.run(Unknown Source)
at rs.Client.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
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Why does the user get this problem without using VPN? With VPN, that user can play just fine, but using VPN as a solution is bad habit.
I appreciate the help if I get any.

What I've tried so far:
1) Disabling firewall to see if firewall is the issue. It wasn't.

Problem solved!
Had to clear SSL state because client downloaded assets from web page and user could not access the website. It gave ERR_SSL_PROTOCOL_ERROR. Now all good.