Plugin clashing with WP External Links

Hi, so I used to have an issue with wp external links where the posts would not be saved due to an JSON error. They resolved this issue in an update around 2-3 months back but recently this error starting coming back again. I asked them but they said they did not change anything so it must be a clash with another plugin. I used wordpress’ troubleshooting to figure out which plugin it was and found out it was happening because of some clash with your plugin. I do not know why or how since your plugin was last updated two months back. I have sent a support message to both you and them. Please help me. I do not want to uninstall either of the plugins. They are both great.

my website is https://www.paradigmshift.com.pk

Please help

Thanks