Prity sure you had a bad connector or one that was not properly put together, or most often, a dirty connector.
I was converted to these connectors by some RC racing guys who swear by them as the only connector able to handle there currents.
Have used these in 350Watt LED setups extensively.
Make sure connectors are clean and dry before assembling, and that they are pushed in all the way.
Here is my guide for replacing your faulty XT60 connectors... if you have an Ender 3 this is probably a good idea.
https://makersteve.com/2019/04/16/safety-first-replace-those-bad-xt60-connectors-ender-3-fix/
Steve
Prity sure you had a bad connector or one that was not properly put together, or most often, a dirty connector.
I was converted to these connectors by some RC racing guys who swear by them as the only connector able to handle there currents.
Have used these in 350Watt LED setups extensively.
Make sure connectors are clean and dry before assembling, and that they are pushed in all the way.