Slow Server Behind NAT

Hello all I have a weird issue I have a server behind NAT and it serves HTTP/HTTPS traffic to the internet it is unbearably slow so I captured packets for this server both on client, server, inside interface of the router and outside interface of router this is what I find:

Client: when trying to connect I get a huge amount of retransmission and timeouts before connecting

outside interface of the router (Receiving side/Before NAT): I have the same amount of retransmissions and timeouts until the server responds.

inside interface of the router (connected to server/Behind NAT): I don't have the retaliations and timeouts I only have the successfully connected session I have checked the raw segment ID for the SYN and SYN/ACK packets.

Server: the same as the behind NAT interface I only have successfully connected session.

all of this has led me to believe it is NAT but I don't know how NAT can cause this.

I have also tried with the extendable nat but same results.

this is my nat statements:

ip nat name <HTTP> inside source static tcp IN_IP 80 OUT_IP 80 extendable

ip nat name <HTTP> inside source static tcp IN_IP 80 interface OUT_INTERFACE 80

I have to note that the retransmits until a successful connection is both random and it takes about 30 seconds.