Upgrade from 7.7.1 to 7.73


I just upgraded current version 7.7.1 to 7.7.3 using “Upgrade Wizard”.
When I try to create any campaign the following message appears:

Warning: Invalid argument supplied for foreach() in /home/proce761/public_html/crm771/modules/Campaigns/WizardNewsletter.php on line 399

i’m not sure if this warning is related with php version.
Thanks in advance

Please provide your System Configuration, read this documentation https://suitecrm.com/wiki/index.php/Compatibility_Matrix in there you have the requirements and minimum configuration for each version

best regards