Error after submitting donation

Hi,
Recently we have been getting an error after submitting a donation. Our donations go through Square. We have tried multiple browsers, disabling plugins and changing themes. The system report is below. Any help would be much appreciated.

### WordPress Environment ###

Home URL: https://www.friendscclibrary.org
Site URL: https://www.friendscclibrary.org
WP Version: 5.2.4
WP Multisite: –
WP Memory Limit: 768 MB
WP Debug Mode: –
WP Cron: ✔
Language: en_US
Permalink Structure: /%category%/%postname%/
Show on Front: page
Page on Front: HOME (#2)
Page for Posts: Unset
Table Prefix Length: *****Secret****
Table Prefix Length: 5
Table Prefix Status: Acceptable
Admin AJAX: Accessible
Registered Post Statuses: publish, future, draft, pending, private, trash, auto-draft, inherit, request-pending, request-confirmed, request-failed, request-completed, acf-disabled, flamingo-spam, refunded, failed, revoked, cancelled, abandoned, processing, preapproval, tribe-ea-success, tribe-ea-failed, tribe-ea-schedule, tribe-ea-pending, tribe-ea-draft, tribe-ignored

### Server Environment ###

Hosting Provider: DBH: localhost, SRV: http://www.friendscclibrary.org
TLS Connection: Connection uses TLS 1.2
TLS Connection: Probably Okay
Server Info: Apache
PHP Version: 7.1.30
PHP Post Max Size: 128 MB
PHP Time Limit: 120
PHP Max Input Vars: 3000
PHP Max Upload Size: 128 MB
cURL Version: 7.59.0, OpenSSL/1.0.2r
SUHOSIN Installed: –
MySQL Version: 5.6.40
Default Timezone is UTC: ✔
fsockopen/cURL: ✔
SoapClient: ✔
DOMDocument: ✔
gzip: ✔
GD Graphics Library: ✔
Multibyte String: ✔
Remote Post: ✔
Remote Get: ✔

### GiveWP Configuration ###

GiveWP Version: 2.5.9
GiveWP Cache: Enabled
Database Updates: All DB Updates Completed.
Database Tables: ✔ wpoe_give_donors – 1.0✔ wpoe_give_donormeta – 1.0✔ wpoe_give_comments – 1.0✔ wpoe_give_commentmeta – 1.0✔ wpoe_give_sessions – 1.0✔ wpoe_give_logs – 1.0✔ wpoe_give_logmeta – 1.0✔ wpoe_give_formmeta – 1.0✔ wpoe_give_sequential_ordering – 1.0✔ wpoe_give_donationmeta – 1.0
GiveWP Cache: Enabled
GiveWP Cache: ✔New Donation✔Donation Receipt❌New Offline Donation❌Offline Donation Instructions❌New User Registration❌User Registration Information✔Donation Note❌Email access
Upgraded From: 2.5.8
Test Mode: Disabled
Currency Code: USD
Currency Position: Before
Decimal Separator: .
Thousands Separator: ,
Success Page: https://www.friendscclibrary.org/donation-confirmation/
Failure Page: https://www.friendscclibrary.org/donation-failed/
Donation History Page: https://www.friendscclibrary.org/donation-history/
GiveWP Forms Slug: /donations/
Enabled Payment Gateways: Square
Default Payment Gateway: Square
PayPal IPN Verification: Enabled
PayPal IPN Notifications: N/A
Donor Email Access: Disabled
Stripe Webhook Notifications: N/A

### Active GiveWP Add-ons ###

Give – Form Field Manager: ✔ Licensed – by GiveWP – 1.4.3

### Theme ###

Name: Avada
Version: 6.1.0

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