> ## Documentation Index
> Fetch the complete documentation index at: https://docs.aviatrix.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Troubleshooting Transit Gateway Connections

> To Troubleshoot Transit Gateway Connections:

To Troubleshoot Transit Gateway Connections:

1. Go to **Aviatrix CoPilot > Diagnostics > Cloud Routes**.
2. **Check IPsec Tunnel**: For BGP learned routes, select the **BGP Info** tab,
   find the gateway, and check if the IPsec tunnel is in Up state. If it is not,
   select the Gateway Routes tab, find the gateway, and click the **Gateway
   Diagnostics** icon on the right. Since all BGP sessions run inside IPsec
   tunnel, this is the first thing you should check.
3. **Check BGP Session**: For BGP learned routes, check if BGP session is
   established. Go to the **BGP Info** tab, expand the gateway, and make sure
   the BGP session is in Established State. If it is not, go to the Gateway
   Routes tab, find the gateway, and click the **Gateway Diagnostics** icon on
   the right. Select the transit gateway, run commands, such as "show ip bgp".

Other ways to troubleshoot:

1. **Check Route Database** For all routes, check if the CoPilot see all the
   learned routes from TGW, BGP, Transit Peering, and Static.
2. **Check Aviatrix Transit Gateway Programmed Routes** Review gateway routes
   for Transit Gateways. Make sure the route you are looking for is in the table
   and has a next hop with metric 100 or lower.
3. **Sync Routes** If for any reason the Route Database on the Aviatrix Platform
   become inconsistent with the Aviatrix Transit Gateway route table,
   [sync the routes](https://legacy.docs.aviatrix.com/documentation/latest/network/tgw-vpc-attachment-create.html)
   to force program the routes on the gateway again.

If any of the above steps show failure, there is an error, please open a support
ticket at [Aviatrix Support Portal](https://support.aviatrix.com) for more
debugging assistance.

If all above steps succeed, the connectivity issue lies somewhere else. Check
Spoke VPC/VNet route table and TGW route table if applicable.

If this is TGW based deployment,
[run an audit](https://legacy.docs.aviatrix.com/documentation/latest/network/tgw-vpc-attachment-create.html#vpc-audit-routes).
Any missing routes in either VPC/VNet route table or TGW route table should be
discovered.