Roll the awning back up to observe how tight it is.
Caravan awning sagging.
Feed a hex screw though the side edges of the awning.
When the fabric starts to sag again extend the fabric out an extra 1 or 2 inches a time to keep it tight.
Screw the other side of the awning in place using a second hex screw.
You can leave the support arms hanging freely but it might help to simply slide the stops back into the leg channel.
Here is brad taylor showing how to adjust an awning fabric.
You do not need to put the screws back in.
Tension is the main cause of water pooling in your awning.
Awnings rely on a solid supportive frame to keep the fabric stretched flat and tight.
The problem seems to be because the awning is 3 5metres deep there is a full extra set of poles at 2 5metres and because the extra front metre is tight its stops the main 2 5 metre roof from tightening.
Turn the screw into the mounting bracket with a ratchet so that the awning sits tightly in place.
Poor tension typically results in a saggy center which acts as a water collection pool.